[gdal-dev] gdalwarp with gauss resampling

[Frank Warmerdam]

On 11-01-12 08:53 AM, Jan Hartmann wrote:
> Is it possible to use gauss resampling with gdalwarp? The current resampling
> options (cubic, bilinear etc) work very well as long as the pixels in input and
> output rasters are about the same size, but not very well when downsampling to
> a much coarser scale. Gdaladdo has gauss resampling, but only for overviews of
> an existing file. I want to combine many mapsheets into one large map at a much
> lower resolution using gauss resampling. Would it make sense/be possible to add
> gauss resampling to gdalwarp itself/ Alternatively, is it possible to extract
> the overviews from a gdaladdo-ed file als regular rasters?

Jan,

No, gdalwarp does not support gaussian resampling.

Yes, it might be desirable to add it though by it's nature gdalwarp isn't
a great engine to severely downsample images as part of a warp.

Yes, you can dump overviews to a standalone file using the "dumpoverviews"
commandline application.  I don't think it is built by default so you might
need to go into gdal/apps and make it explicitly.

You could also do a gdal_translate at the resolution of an overview and
it should essentially just extract the overview though that might not be
a completely sure thing.

Best regards,
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