Hopefully some one can answer this simple questions. I read the manual and searched but cannot figure out that when I am driving the map show half gray and half green. I thought it may be township lines, county lines, homes vs business lines and all these are incorrect. Hopefully one of you can toss me a bone and let me know what the different colors mean...

The different colors have a distinct value for each one. In a nutshell, they all reflect the fact that the stereo is a turd. But you probably know this already.

I've noticed that park boarders (i.e. Yellowstone Park) are defined in green