RFC 4 - Resampling Examples

Steve Lime steve.lime at DNR.STATE.MN.US
Mon Sep 19 14:50:18 EDT 2005


The samples look terrific, a very welcome addition. Let me know if you'd like me
to take on some of the WCS work. 

>>> Frank Warmerdam <warmerdam at POBOX.COM> 09/18/05 1:21 PM >>>
Folks,

I have a preliminary version of average, and bilinear resampling
working in my local mapserver per RFC 4.  Some results are available
at:

  http://home.gdal.org/~warmerda/resample/ 

In the process of doing this work, I have also removed the requirement
to have coordinate systems in order to use the code in mapresample.c.
That means that RESAMPLE= options, rotated input images, and
rotated output maps can now all be generated without requiring 
coordinate system information on the map and all raster layers as
was the need before.  

A few other things have also occured to me since writing the RFC.

 1) Currently mapresample.c aims to load the source image at 
     double the resolution of the target image.  To some extent this
     is going to defeat the resampling logic which ought to be operating
     against the full resolution data for full effect.  The LOAD_FULL_RES_IMAGE
     PROCESSING option can be used to work around this. 

 2) The RFC should also address connecting up WCS support for resampling.
     The WCS specification includes resampling options of which we had
     only been supporting NEAREST.  I am willing to commit to WCS 
     support for other resamplers as well. 

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



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