WMS disable no-square requests

[assefa]

The map file level configuration described in the docs as: MS_NONSQUARE [yes|no] :The CONFIG parameter can be used to allow non-square WMS requests.

does not really disable non-square requests in the case of WMS. It will be turned on always.

Is there a reason why It should always be turned in WMS?

This is related to issues we are having for vector type outputs such as KML through WMS (#3928)

[dmorissette]

If I remember correctly, WMS requires that you return non-square pixels if the width/height (pixels) ratio does not match the dx/dy ratio of the geographic bbox. If you want square pixels with WMS then you have to make sure your WMS GetMap request passes a geographic BBOX with the correct proportions for the requested width/height.

[assefa]

But disabling it for vector type outputs such as KML obtained through WMS GetMap would make sense, right?

[assefa]

Discussion on IRC:

The idea would be to allow some drivers (for now only KML) to be able to adjust the width/height to fit the ratio of the extents for a non-square wms type requests.

This could be triggered by some output format configuration. The idea is to not have ifs with driver name. This would be done between mapwms.c (load parameters function) or mapdraw.c (prepareimage). Quickly checking the code I was not sure where the best place would be that would not afftect existing functionallities.