[pct-l] Understanding halfmile's maps

[Meike]

I really like the halfmile maps. But I have some problems in 
interpreting them. Might not be of real importance, but I always like to 
understand what I see :)

Is there any... any... I don't even know what that's called in english. 
Legend maybe? Explanation what the symbols, colors, hatchures, lines are 
supposed to tell me. Is there anything like that?

I am particulary interested in the red lines that most of the time run 
roughly parallel to the WGS84 grid, but not quite, and sometimes not at 
all, and sometimes at differing distances... what are those? There are 
thicker red lines, too - sometimes combined with a dotted black line. 
Look like some kind of border. Border to state parks, reservations and 
so on? And what are those usually rectangular areas with darker colors?

Thanks for any clarification,
Meike