ugh, sorry just realized my comment (sentence begins 'Further ...') about "scaling" is completely irrelevant - you mean spatial and not data scaling. Just ignore that one sentence.
Cheers, Mike On Fri, Jan 6, 2023 at 10:36 AM Michael Sumner <mdsum...@gmail.com> wrote: > in short, warp will give you exactly the target extent of a (possibly) new > grid specification in that -te subdivided by the -ts. > > translate will give you approximately the extent provided to projwin, but > snapped to the source grid alignment at a particular zoom implied by the > projwin subdivided by the outsize. > > Further, translate can do scaling but warp cannot, which I guess is why > you have a vrt in the workflow - you can scale a source virtually with > translate to vrt, then warp (or translate) that. > > (Finally it's a bit sloppy to have such arbitrary extent values that warp > will preserve and I routinely snap them to the source alignment, and I'm > interested to provide such a feature in the warper options too.) > > Hope that helps! > > > > > > > On Fri, 6 Jan 2023, 03:16 Daniel Mannarino, <daniel.mannar...@gmail.com> > wrote: > >> Hi folks! >> >> >> >> We have a process that generates web mercator zoom levels by resampling >> from the next higher up, from the original resolution down to zoom level 0. >> Currently we do so with gdalwarp, but a team member realized that >> gdal_translate is capable of the same, and at first glance is much faster. >> Unfortunately, using the two commands (below) which I intended to do >> exactly the same thing winds up with slightly different results (can/should >> I post a small image here to illustrate?). >> >> I won't ask "Which is correct?" because the answer is almost certainly >> "That depends on what you want". But can someone help me understand the >> difference between what is done with the gdalwarp command versus the >> gdal_translate one so that I can decide if using gdal_translate is an >> acceptable solution? Here are the two commands: >> >> >> >> gdalwarp -te 12523442.714243278 0.0 15028131.257091936 2504688.5428798534 >> -ts 65536 65536 -r mode -co TILED=YES ../source_tiles/everything.vrt >> 007R_013C_warp_mode.tif >> >> >> >> gdal_translate -r mode -projwin 12523442.714243278 2504688.5428798534 >> 15028131.257091936 0.0 -outsize 65536 65536 -co TILED=YES >> ../source_tiles/everything.vrt 007R_013C_translate_mode.tif >> >> >> >> Thank you! >> >> Daniel Mannarino >> _______________________________________________ >> gdal-dev mailing list >> gdal-dev@lists.osgeo.org >> https://lists.osgeo.org/mailman/listinfo/gdal-dev >> > -- Michael Sumner Software and Database Engineer Australian Antarctic Division Hobart, Australia e-mail: mdsum...@gmail.com
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