[Mapserver-dev] non-square pixels and WMS

[Frank Warmerdam]

Folks,

I have committed preliminary support for non-square pixels for use in WMS
mode.  It is enabled by adding "CONFIG MS_NONSQUARE YES" in the main map
configuration section.  It has the following affect:

  o Avoid calling msAdjustExtent() in msDrawMap().
  o Set map->cellsize to be the average of the x and y cellsize.
  o Turns on use of geotrasnform (sets map->gt.need_geotransform to TRUE),
    but only if the x and y pixelsize differ.

So, it suffers from all the side-effects of my existing rotation hackery,
plus the scale may be inaccurate.

I anticipate adding a new keyword to the mapfile to control this ability
at some point in the future ... suggestions are welcome.  I am using the
CONFIG keyword for now mainly so we can test the capability before we have
hashed out all details.

So, anyone who wants to have a WMS that can response to non-square pixel
requests, grab the latest 4.3 from CVS and try it out.

Note, there is also a test for this logic in msautotest/gdal/nonsquare.map.

Best regards,
-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent