I hunted around the forums for this old plug-in and couldn't find it, and, since the RTR forums are down right now, I re-uploaded the plug-in to filefront.
This plug-in simply restores the standard (vanilla Rome Total War) campaign map ground color and removes the ugly ones (IMO) introduced in RTR. I, and other Rome Total Realism fans prefer the pre-RTR6.3 map colors to the ones created by BDH for RTR6.0 Gold and Platinum.
To install, simply unzip the .rar file, which will create a folder called ground_types. Place the ground_types folder in your /Data/Terrain/Aerial_map folder.
Note: This is save game compatible.
Yours Truly,
Candelarius
DOWNLOAD LINK