[mapserver-users] How to use MINSCALEDENOM & MAXSCALEDENOM with dynamic image size?

[John Maurer]

Dear MapServer Users,
Defining a minimum and maximum scale denominator for a layer seems 
problematic to me when the resulting image size can be arbitrarily 
specified by the end user. For instance, doubling the image size (e.g. 
400px to 800px) on the same map will double the scale denominator (e.g. 
24,000 to 48,000)--a layer may display at one image size but not the 
other because of this. A more useful criteria would be to specify the 
minimum and maximum pixel size for a layer (e.g. 1 km and 5 km), which 
is independent of the image size. This must be a common problem for 
MapServer application developers since a WMS call requires an image 
width and height. Has anyone come up with a workaround for this? Or am I 
understanding things incorrectly? Thanks for any help!
Best Regards,

-- 
John Maurer
Web/Database Applications Engineer
National Snow and Ice Data Center (NSIDC)
University of Colorado at Boulder
http://cires.colorado.edu/~maurerj
+1-303-586-1677
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"Without geography, you're nowhere!"