World files are external text coordinate reference files. They contain XY coordinate information for each pixel in an image by specifying the real world XY coordinates of the upper left pixel in the image and specifying the resolution (or number of units for each pixel) in the X and Y directions.
World files have the extension of the first and last letters of the image extension followed by a W. So for a TIF file, the world file would have the extension TFW. For a JPG, the world file would have the extension JGW.
A World file is a 6-line text file. You can create your own file in a text editor program like Notepad:
- Open up your desired text editor program.
- Enter these values:
x resolution <--the number of real world units per pixel in the X direction
amount of translation <--usually 0 or a very small number
amount of rotation <--usually 0 or a very small number
negative of the y resolution <--the negative of the number of real world units per pixel in the Y direction
xMin coordinate (upper left)
yMax coordinate (upper left) - Save the file with the appropriate file extension (TFW, JGW, PGW, etc) to the same folder as the image file, with the same file name as the image file.
Note that world files don't contain any projection information.
Updated September 4, 2020
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