[mapserver-users] map scale questions

[Alex Rice]

Hi, I think my mapserver scale output is wrong, and my scalebar 
graphic is definitely skewed. I am stumped after looking at the 
docs, tutorials and the mailing list archive.

I have a map table which viewed in MapInfo Pro tells me, the 
Scale: 1 in = 3 mi (for this particular extent I am looking at).

So, in my mapfile MAP section I put
UNITS miles
and in my mapfile SCALEBAR section I put
UNITS miles

Then I view the same map & approx same extent in mapserver (OGR 
reading mapinfo .tab), I get from mapserver scale = 1 : 5015 and 
the scalebar renders as 1 bar = 0.16 mi. Clearly this is way off 
from the 1 in = 3 mi which Mapinfo was saying.

But also mapserver scale 1:5015 does not equal the scalebar 1 
bar = 0.16 mi !
If the scalebar is 1 inch, then 1 inch = 5015 inches = 418 feet = 
0.079 mi.

So it's as if Mapinfo, the mapserver [scale] and the mapserver 
scalebar image all are using different scales?

I am using no projections in my mapfile. I have saved all my 
Mapinfo files with a common projection so I can avoid 
reprojecting in mapserver. Do I need projections defined to make 
the scale come out correctly?

I am just really confused about how to get mapserver to display 
the same scale as Mapinfo Pro. Any suggestions would be 
appreciated.

TIA

Alex Rice, Software Developer
Architectural Research Consultants, Inc.
alex_rice at arc.to
alrice at swcp.com