Hi, gdaladdo [1] provides some more interpolation methods. It is designed specifically for down-sampling. To create a new GeoTIFF, use it with the -ro option and the levels set to 2,4,8 and 15. The value 15 makes sure you get an overview at 1/15 th of the original resolution.
[1]: http://www.gdal.org/gdaladdo.html On Thu, Dec 15, 2011 at 3:06 AM, Etienne Tourigny <[email protected]>wrote: > The only option that you do *not* have is "mode" (the dominant value), > which can be useful in the case of categorical (integer) data. That > question has been answered here: > > http://www.osgeo.org/pipermail/gdal-dev/2011-August/029692.html > > On Wed, Dec 14, 2011 at 1:35 PM, Travis Kirstine > <[email protected]> wrote: > > Andreas, > > > > Yes gdalwarp support various resampling methods > > > > To use different resampling methods use the -r flag followed by the > method > > > > eg > > > > gdalwarp -r near .............. > > gdalwarp -r bilinear ............. > > > > etc... > > > > > > > > > > On 14 December 2011 08:26, Andreas H. <[email protected]> wrote: > >> Travis, > >> > >> thanks for your answer! > >> > >> Regarding the resampling methods: Do they all just interpolate the > data? I > >> mean, when downsampling, usually I would use mean() or something similar > >> to fill the new (coarser) grid cells. Doas gdalwarp actually do this and > >> I'm not able to understand the documentation, or is it different? > >> > >> Thanks again! > >> Andreas. > >> > >> > >>> Andreas, > >>> > >>> gdalwarp can be used to resample images using the -tr flag or -ts flag. > >>> > >>> For example resample 1m image to 10m using cubic resampling and > >>> "target resolution' > >>> > >>> gdalwarp -r cubic -tr 10 10 input_1m.tif output_10m.tif > >>> > >>> You may have an issue determining the output resolution as I believe > >>> the resolution will be in decimal degrees rather than arc-seconds. > >>> > >>> Regards > >>> > >>> On 13 December 2011 14:52, Andreas H. <[email protected]> wrote: > >>>> Hi, > >>>> > >>>> let's say I have a GeoTIFF file with a global grid in a 30 arc-second > >>>> resolution. Which would be the appropriate GDAL command to spatially > >>>> down-sample this file to say 0.125°? > >>>> > >>>> Thanks for your insight, > >>>> Andreas. > >>>> _______________________________________________ > >>>> gdal-dev mailing list > >>>> [email protected] > >>>> http://lists.osgeo.org/mailman/listinfo/gdal-dev > >>> > >> > >> > >> _______________________________________________ > >> gdal-dev mailing list > >> [email protected] > >> http://lists.osgeo.org/mailman/listinfo/gdal-dev > > _______________________________________________ > > gdal-dev mailing list > > [email protected] > > http://lists.osgeo.org/mailman/listinfo/gdal-dev > _______________________________________________ > gdal-dev mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/gdal-dev > -- Best regards, Chaitanya kumar CH. +91-9494447584 17.2416N 80.1426E
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