World Files

World files are plain text files used along side a normal image file. The world file tells a GIS program how to render the image. The filename is the same as the main image, with a different extension:

actual image fileworld file extension
jpgjgw
tiftfw

The contents of a world file consist of six lines, as shown in the following example:

line #example valuedescription
10.17578125x-scale value
20y rotation/skew
30x rotation/skew
4-0.17578125y-scale value * I think this always needs to be negative
5-180top-left x coordinate
690top-left y coordinate

* Note that the coordinates need to be in the units of the actual projection of the image