I want to understand how "world files" are created. I found some definitions, like:
http://en.wikipedia.org/wiki/World_file
which says that the 2 last lines in the file are x and y coordinates of the center of the upper left pixel. I want to know if those coordinates may be given in decimal degrees? All examples I found gave UTM coordinates without the zone, what means one just cannot know where the image is from!
Am I missing something important here?