[gdal-dev] Downsampling with gdalwarp

[Stanley Glidden]

Hi,

Can someone tell me if anything has changed in terms of being able to
downsample using averaging with gdalwarp. I found a post from a few years
back that said the only way to accomplish this is through an option in the
virtual file driver. Is this still the case? If so what is the syntax to downsample
with the virtual file driver?

Thanks.

sjg


>From the post a few years back:

http://lists.osgeo.org/pipermail/gdal-dev/2004-March/002231.html

For the kind of downsampling you seem to want to do, I think the averaging
is
the best approach.  Unfortunately, that is not currently offered by
gdalwarp,
and because of the non-linear (in general) nature of the geometric
transformations in gdalwarp, it would be hard to implement "averaging"
appropriate.  It is however available in the overviewing building code and
as an option in the virtual file driver.  Perhaps I should have a convenient
way of downsampling images with averaging via a GDAL utility ... perhaps
gdal_translate or a custom algorithm.