Should point out that there are 2 different methods at play here. Most traditional solutions involve editing the palettes (forest.ppl, winter.ppl ... etc) that are included in the game 'mpq' data files.
If you want you can use mpq tools to extract the .ppl files then edit them with my palette editor
then either replace the originals in War2Dat.mpq or include the updated files in War2Patch.mpq (which will be used in place of the War2Dat versions).
The patcher above uses a different approach where it mods the wc2 exe so that it uses a different palette entry (color) to display a mini-map color without actually changing the palette at all.
The advantage of the patcher is that it is a quick and easy 1-step fix. The only disadvantage is that I *think* it upsets War2bneInsight, for no reason other than Insight checks the exe then refuses to work because it doesn't recognise the changed exe as a valid version.
I say "I think" because maybe it is some other exe mod I have done that upsets it lol not sure. Perhaps some one else can confirm this?