hey hey!
Happy to see my tool is still useful after so many years.
As for the terrain, if I recall properly after so long, it is a mix from TERRAIN.SS and PHYS0.SS. Terrain.ss is the base tile, and phys0.ss contain things like tile transition masks, roads, rivers, mountains, etc, and that is drawn over the main tile. Not sure if that's all, but hey, long time since I delved into anything Colonization-related.
My tool can extract the images, but one by one, shouldn't be hard to change it to export all the images in a sprite series. If you need or don't know how to do that, I can do it and post here.