The .SRF files are sprites that are used to draw the features on the ground. Unline GND files, these sprites contain 25 frames that can be stitched together to draw details such as roads or boundaries between areas.
These sprites are taken from DESERT.SRF and illustrate how the frames fit together. The first frame in the exploded version is the bottom left, the last frame is the top right.
|Exploded Version||Stitched Version|