Is it possible for a map to have more than one ground texture?

I don't know If I'm using my terms right, I'm talking about the texture in the map that draws where which textures go, and what shade they are, like in a path or road, or a lightly shaded dirt area around a base.

I need an additional ground texture because I am creating a vast underground cavern in my map. It too will have paths.

edit: you're missing my point. can you have more than one of these!:
http://img509.imageshack.us/my.php?image=bloodground.tif


im not talking about alpha maps, or secondary detail maps.
Edited by Merkatroyd on Apr 19, 2009 at 11:38 PM

You can have multiple textures. If you need the same texture but lighter you need to copy and edit the original then make it lighter.

he means a umm... whats it called. like this (its for BG): http://img509.imageshack.us/my.php?image=bloodground.tif

Yes you can, it's the alpha layer that shows where the texture is.

yup. the alpha in the tiff controls the use of the primary and secondary detail maps.
and the number below the detail maps slots in the ground shader controls the tiling of the detail maps.

I have been having issues finding that option too. I have Adobe Photoshop CS3 and i can't seem to find how to paint that on. Do you just make a completely new transparent layer after putting a base map down and then paint the roads over it? or is there a way to physically paint it on?