Введение
Файл географических данных — это шестистрочный текстовый файл-компаньон, используемый географическими информационными системами (ГИС) для геопривязки растровых изображений карт. Спецификация файла была введена компанией Esri и имеет следующий вид:
Geographic data file
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
Строка 1: A: размер пикселя в направлении x в единицах карты на пиксель
Строка 2: D: поворот вокруг оси y
Строка 3: B: поворот вокруг оси x
Строка 4: E: размер пикселя в направлении y в единицах карты, почти всегда отрицательный
Строка 5: C: координата x центра верхнего левого пикселя
Строка 6: F: координата y центра верхнего левого пикселя
Geographic data file
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
Однако это описание вводит в заблуждение, поскольку параметры D и B не являются угловыми поворотами, а параметры A и E не соответствуют размеру пикселя, если D или B не равны нулю. Параметры A, D, B и E иногда называют «масштаб по x», «наклон по y», «наклон по x» и «масштаб по y». Более точное описание параметров A, D, B и E:
Geographic data file
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
Строка 1: A: компонента ширины пикселя по оси x (масштаб по x)
Строка 2: D: компонента ширины пикселя по оси y (наклон по y)
Строка 3: B: компонента высоты пикселя по оси x (наклон по x)
Строка 4: E: компонента высоты пикселя по оси y (масштаб по y), обычно отрицательная
Строка 5: C: координата x центра верхнего левого пикселя исходного изображения, преобразованная в систему координат карты
Строка 6: F: координата y центра верхнего левого пикселя исходного изображения, преобразованная в систему координат карты
Geographic data file
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
Все четыре параметра выражены в единицах карты, которые определяются пространственной системой отсчета растра. Когда D или B не равны нулю, ширина пикселя определяется как:
Geographic data file
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
а высота пикселя как:
Geographic data file
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
Файлы world, описывающие карту в системе координат Universal Transverse Mercator (UTM), используют следующие соглашения:
D и B обычно равны 0, поскольку пиксели изображения обычно выравниваются по сетке UTM.
C — это восточная координата UTM.
F — это северная координата UTM.
Единицы измерения всегда выражаются в метрах на пиксель.
Geographic data file
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
Вышеописанное относится также к прямоугольному, невращающемуся изображению, которое может быть, например, наложено на ортогонально спроецированную карту. Однако, если файл world описывает изображение, повернутое относительно оси целевой проекции, то A, D, B и E должны быть выведены из необходимого аффинного преобразования (см. ниже). В частности, A и E больше не будут представлять собой измерение в метрах на пиксель по соответствующим осям. Эти значения используются в шестипараметрическом аффинном преобразовании:
Geographic data file
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
которое можно записать в виде следующего набора уравнений:
Geographic data file
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
где:
Geographic data file
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
x''' — вычисленная восточная координата UTM пикселя на карте
y''' — вычисленная северная координата UTM пикселя на карте
x — номер столбца пикселя в изображении, отсчитываемый слева
y — номер строки пикселя в изображении, отсчитываемый сверху
A или масштаб по x: размер пикселя в единицах карты в направлении x
B, D — параметры наклона
C, F — параметры сдвига: координаты x и y центра верхнего левого пикселя на карте
E — отрицательный масштаб по y: размер пикселя в единицах карты в направлении y
Geographic data file
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
Масштаб по y (E) отрицательный, поскольку начала координат изображения и системы координат UTM различны. Начало координат изображения находится в верхнем левом углу, а начало координат системы координат карты — в нижнем левом углу. Значения строк в изображении увеличиваются вниз от начала координат, в то время как значения координат y на карте увеличиваются вверх от начала координат. Многие картографические программы не могут обрабатывать «перевернутые» изображения (т. е. с положительным масштабом по y). Чтобы перейти от UTM (x', y') к позиции пикселя (x, y), можно использовать следующее уравнение:
Geographic data file
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
Пример:
Исходное изображение falknermap.jpg имеет размер 800×600 пикселей (карта не показана). Его файл world — falknermap.jgw и содержит:
Geographic data file
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
32.0
0.0
0.0
32.0
691200.0
4576000.0
Geographic data file
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
Положение маяка острова Фолкнер на изображении карты:
x = 171 пиксель слева
y = 343 пикселя сверху
Geographic data file
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
Это дает:
x1 = 696672 метров (восточная координата)
y1 = 4565024 метров (северная координата)
Geographic data file
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
Зона UTM (сетки) не указана, поэтому координаты неоднозначны — они могут представлять собой положение в любой из примерно 120 зон сетки UTM. В этом случае приблизительная широта и долгота (41.2, −072.7) были найдены в географическом справочнике, и зона UTM (сетки) была определена как 18 с помощью веб-конвертера.
Geographic data file
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
A world file is a six line plain text sidecar file used by geographic information systems (GIS) to georeference raster map images. The file specification was introduced by Esri.) is:
Line 1: A: pixel size in the x direction in map units/pixel
Line 2: D: rotation about y axis
Line 3: B: rotation about x axis
Line 4: E: pixel size in the y direction in map units, almost always negative
Line 5: C: x coordinate of the center of the upper left pixel
Line 6: F: y coordinate of the center of the upper left pixel
This description is however misleading in that the D and B parameters are not angular rotations, and that the A and E parameters do not correspond to the pixel size if D or B are not zero. The A, D, B and E parameters are sometimes named "x scale", "y skew", "x skew" and "y scale". A better description of the A, D, B and E parameters is:
Line 1: A: x component of the pixel width (x scale)
Line 2: D: y component of the pixel width (y skew)
Line 3: B: x component of the pixel height (x skew)
Line 4: E: y component of the pixel height (y scale), typically negative
Line 5: C: x coordinate of the center of the original image's upper left pixel transformed to the map
Line 6: F: y coordinate of the center of the original image's upper left pixel transformed to the map
All four parameters are expressed in the map units, which are described by the spatial reference system for the raster. When D or B are non zero the pixel width is given by:
and the pixel height by
World files describing a map on the Universal Transverse Mercator coordinate system (UTM) use these conventions:
D and B are usually 0, since the image pixels are usually made to align with the UTM grid
C is the UTM easting
F is the UTM northing
Units are always meters per pixel
The above description applies also to a rectangular, non rotated image which might be, for example, overlaid on an orthogonally projected map. If the world file describes an image that is rotated from the axis of the target projection, however, then A, D, B and E must be derived from the required affine transformation (see below). Specifically, A and E will no longer be the meter/pixel measurement on their respective axes. These values are used in a six parameter affine transformation:
which can be written as this set of equations:
where:
x''' is the calculated UTM easting of the pixel on the mapy' is the calculated UTM northing of the pixel on the mapx is the column number of the pixel in the image counting from lefty is the row number of the pixel in the image counting from topA or x scale; dimension of a pixel in map units in x directionB, D are rotation termsC, F are translation terms: x, y map coordinates of the center of the upper left pixelE is negative of y scale: dimension of a pixel in map units in y direction
The y scale (E) is negative because the origins of an image and the UTM coordinate system are different. The origin of an image is located in the upper left corner, whereas the origin of the map coordinate system is located in the lower left corner. Row values in the image increase from the origin downward, while y coordinate values in the map increase from the origin upward. Many mapping programs are unable to handle "upside down" images (i. e. those with a positive y'' scale). To go from UTM(x'y') to pixel position(x,y) one can use the equation:
Example:
Original falknermap. jpg is 800×600 pixels (map not shown). Its world file is falknermap. jgw and contains:
32.0
0.0
0.0
32.0
691200.0
4576000.0
The position of Falkner Island light on the map image is:
x = 171 pixels from left
y = 343 pixels from top
This gives:
x1 = 696672 meters Easting
y1 = 4565024 meters Northing
The UTM (grid) zone is not given so the coordinates are ambiguous — they can represent a position in any of the approximately 120 UTM grid zones. In this case, approximate latitude and longitude (41.2, −072.7) were looked up in a gazetteer and the UTM (grid) zone was found to be 18 using a Web based converter.
Локализация
При создании файлов мира рекомендуется игнорировать настройки локализации и всегда использовать "." в качестве десятичного разделителя. Также, отрицательные числа следует указывать исключительно символом " ". Это обеспечивает максимальную переносимость изображений.
When writing world files it is advisable to ignore localization settings and always use "." as the decimal separator. Also, negative numbers should be specified with the " " character exclusively. This ensures maximum portability of the images.