[gdal-dev] Re: Strange things with gdalwarp ...

[Mateusz Loskot]

Adam Nowacki wrote:
> Some rather counterintuitive gdalwarp behavior: the bigger
> dfWarpMemoryLimit (-wm setting) the more cpu time will be wasted on
> warping not existing pixels. Why? Warping begins with the destination
> window size of entire output image size. If this size is larger than
> dfWarpMemoryLimit it is split in half along the longest axis and any
> half that doesn't contain the currently processed source file is
> discarded. With large dfWarpMemoryLimit this subdivision process will
> stop early with still large portions of out of source image pixels.

It's really good piece information that belongs to FAQ

http://trac.osgeo.org/gdal/wiki/FAQ

Best regards,
-- 
Mateusz Loskot, http://mateusz.loskot.net
Charter Member of OSGeo, http://osgeo.org