Andreas I think thats referring to my suggestion of GMT to do part of the work
On Thu, 2011-12-15 at 14:00 +0100, Andreas H. wrote: > Joaquim, > > > nearneighbor is not really a good thing to use. Grid it with surface. > > What do you mean by "grid it with surface"? In my GDAL (1.8.1), I only > have the following choices: > > Available resampling methods: > near (default), bilinear, cubic, cubicspline, lanczos. > > thanks for your insight, > > Andreas. > > > > > Joaquim > > > > Sent from my iPadiola > > > > On 14/12/2011, at 18:32, "Andreas H." <[email protected]> wrote: > > > >> Travis, > >> > >> yes, thanks, I had already found that in the documentation. I'm just > >> wondering what e.g. 'bilinear' means when I go from a fine to a coarse > >> grid? If GDAL works in terms of "nodes", then I would assume 'bilinear' > >> means interpolation, which in turn would be a very different result from > >> working in terms of "cells" and then taking e.g. the average of all > >> "old" cells in the "new" grid. > >> > >> I hope you see my problem / question. > >> > >> Thanks for you insight, > >> Andreas. > >> > >> Am 14.12.2011 16:35, schrieb Travis Kirstine: > >>> 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 _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
