Ok, let's take for example an excerpt from the mod10 maptrans.txt for 1.5 executeable (1.3 versions are different).
Code:
// (07) Snow
85 07 000 011a 011b 011c 011d
86 07 002 011a 011b 011c 011d
85 means color 85...that means row 8 (and first row is 0), column 5 (again first column is 0)
07 means group 07, then we have 000 for altitude, after that we have 011a-011d, those of course are snow tiles to be placed at random.
The next line is all the same, but altitude of 2.
Now let's say you changed that line to read:
Code:
86 28 000 011a 011b 011c 011d
That would be group 28, which would be your new group, snow at alt 0.
Granted you aren't going to want to cut that particular line but you'll have to find something to sacrifice. Mod11 I've got a little more flexibility planned. Now if you use the 1.362 exe your maptrans will be the same except for the group, group isn't included there but in it's own groups.txt file.
Next step is items.txt, your going to add something like:
Code:
28 0130 0000 0000 6143 4095 SnowForest.txt
And of course you have to create a snowforest.txt script to place your trees and crap.
I still really don't recommend adding new groups for statics placements without heavy consideration. Most times it is avoidable. For instance your oasis would be easy enough to seperate the jungle in that area with a different items script because the jungle in question is going to be surrounded by desert and not even close to your normal jungles.
Now your snowy forest would be tough because you are going to have it interspersed with your normal snow. My suggestion would be to make it say normal dirt for the forest area floor and then again through items.txt change it up.
Depending what stage you are at with this, I could just whip you up some custom scripts to accomplish this if we spent a little time on it.