Scale and Map Units

[Kieran Ames]

Hello again. Kieran here (from my home address, not work!).

I have a question regarding scale and when to render layers and labels.

The data I work with is consistently in decimal degrees. For data I've
received that was in some type of projection, I converted those files to
dec degs.

The data I've seen in the examples around the list use image
_coordinates_. So, a map file entry like
EXTENT 74000 4775000 798000 5500000
might have another line like
MINSCALE 400000 and MAXSCALE 400000 for different layers.
(www.dnr.state.mn.us/mis/gis/gislis99/example4)

I've set my extent information in Decimal degrees like
EXTENT -74.257 40.496 -71.857 41.292  (Long Island, NY)

Questions:
1. What is the proper way of implementing MINSCALE and MAXSCALE
functionality using decimal degrees?
2. My scale bar works, but gives a range like 0.0000 to 0.0002 miles
when I'm looking at a layer that's more than 100 miles across... (Extent
above)

Many thanks.

Kieran