Relationship between Unit dd and MAX/MINSCALE

[Tim Tsai]

Hello.  I have a map file that uses UNIT DD (decimal degrees) but
I can't quite figure out exactly what unit the MAXSCALE/MINSCALE
keywords use.

For example, MINSCALE 100000 seems to be more than 3.2 miles but
less than 6.4 miles.

Thanks,

Tim