[Community] Default map renderer behavior, extents and pixel aspect ratio

[Chris Calloway]

Sean Gillies wrote:
> Allowing non-square (spatial aspect ratio) pixels preserves the  output 
> extent, and I prefer this behavior. How do the rest of you feel?

It ought to be selectable behavior.

Disrespecting the aspect ratio in favor of image size destroys the 
apparent projection while preserving the extents.

Disrespecting image size in favor of aspect ratio destoys extents in 
favor of apparent projection.

People ought to be able to specify which they favor: extents or image 
size to get the results they desire.

Being able to specify image size and extents sets up a potential 
conflict between resolving aspect ratio and apparent projection. It's 
probably a bad thing that both can be specified. But they can. So 
provide intelligent choices about how to deal with the potential conflict.

In the absence of being able to specify which, MapServer takes the 
scientifically correct approach, although maybe not the most visually 
expected approach, of rendering projection faithfully.

Thanks for asking.

-- 
Sincerely,

Chris Calloway
http://www.seacoos.org
office: 17-6 Venable Hall   phone: (919) 962-4323
mail: Campus Box #3300, UNC-CH, Chapel Hill, NC 27599