How to Georeference a Picture File Using a World File

Using a classical text editor you can georeference any kind of raster file (GIF, PNG, JPEG...). Just create a text file with 6 lines as following:

• Line 1: pixel size in the x_direction in map units/pixel.
• Lines 2 and 3: rotation terms.
• Line 4: pixel size in the y_direction in map units.
• Line 5: x_coordinate of the center of the upper left pixel.
• Line 6: y_coordinate of the center of the upper left pixel.

Note: The line 4: pixel size in the y-direction in map units is most of the time a negative number. If the picture looks upside-down in Isatis.neo, try to add or remove a minus at this line.

For more information about how the different parameters are calculated, you can refer to Wikipedia.

Save the file using the same name as the picture file and add a w at this end of the extension or use the extension .wld.