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<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Hi,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">About -separate and multi-band inputs, see
<a href="https://gdal.org/programs/gdalbuildvrt.html#cmdoption-gdalbuildvrt-separate">
https://gdal.org/programs/gdalbuildvrt.html#cmdoption-gdalbuildvrt-separate</a><br>
<br>
“Starting with GDAL 3.8, all bands of each input file are added as separate VRT bands, unless -b is specified to select a subset of them. Before GDAL 3.8, only the first band of each input file was placed into a new VRT band, and -b was ignored.”<br>
<br>
-Jukka Rahkonen-<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b>Lähettäjä:</b> gdal-dev <gdal-dev-bounces@lists.osgeo.org>
<b>Puolesta </b>Lauren?iu Nicola via gdal-dev<br>
<b>Lähetetty:</b> torstai 21. joulukuuta 2023 16.09<br>
<b>Vastaanottaja:</b> gdal-dev@lists.osgeo.org<br>
<b>Aihe:</b> Re: [gdal-dev] Any difference between VRT SimpleSource and no-op ComplexSource?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-family:"Arial",sans-serif">On Thu, Dec 21, 2023, at 15:51, Even Rouault wrote:<o:p></o:p></span></p>
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<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt" id="qt">
<p>It only uses a ComplexSource when it needs to, that is to say when there is nodata or a mask band.<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Arial",sans-serif">I didn't realize this. I think I'm hitting a corner case with
</span><span class="font"><span style="font-family:"Menlo",serif">-separate</span></span><span style="font-family:"Arial",sans-serif">, which is practically the only way I've ever used it:<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif">$ gdalbuildvrt test.vrt T35TMK_20230520T090559_B02_10m.jp2 && cat test.vrt </span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif">0...10...20...30...40...50...60...70...80...90...100 - done.</span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"><VRTDataset rasterXSize="10980" rasterYSize="10980"></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> <SRS dataAxisToSRSAxisMapping="1,2">PROJCS["WGS 84 / UTM zone 35N",GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4326"]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",27],PARAMETER["scale_factor",0.9996],PARAMETER["false_easting",500000],PARAMETER["false_northing",0],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["Easting",EAST],AXIS["Northing",NORTH],AUTHORITY["EPSG","32635"]]</SRS></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> <GeoTransform> 3.9996000000000000e+05, 1.0000000000000000e+01, 0.0000000000000000e+00, 5.0000400000000000e+06, 0.0000000000000000e+00, -1.0000000000000000e+01</GeoTransform></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> <VRTRasterBand dataType="UInt16" band="1"></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> <ColorInterp>Gray</ColorInterp></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> <SimpleSource></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> <SourceFilename relativeToVRT="1">T35TMK_20230520T090559_B02_10m.jp2</SourceFilename></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> <SourceBand>1</SourceBand></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> <SourceProperties RasterXSize="10980" RasterYSize="10980" DataType="UInt16" BlockXSize="1024" BlockYSize="1024" /></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> <SrcRect xOff="0" yOff="0" xSize="10980" ySize="10980" /></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> <DstRect xOff="0" yOff="0" xSize="10980" ySize="10980" /></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> </SimpleSource></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> </VRTRasterBand></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> <OverviewList resampling="nearest">2 4 8 16</OverviewList></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"></VRTDataset></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif">$ gdalbuildvrt -separate test.vrt T35TMK_20230520T090559_B02_10m.jp2 && cat test.vrt</span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif">0...10...20...30...40...50...60...70...80...90...100 - done.</span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"><VRTDataset rasterXSize="10980" rasterYSize="10980"></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> <SRS dataAxisToSRSAxisMapping="1,2">PROJCS["WGS 84 / UTM zone 35N",GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4326"]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",27],PARAMETER["scale_factor",0.9996],PARAMETER["false_easting",500000],PARAMETER["false_northing",0],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["Easting",EAST],AXIS["Northing",NORTH],AUTHORITY["EPSG","32635"]]</SRS></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> <GeoTransform> 3.9996000000000000e+05, 1.0000000000000000e+01, 0.0000000000000000e+00, 5.0000400000000000e+06, 0.0000000000000000e+00, -1.0000000000000000e+01</GeoTransform></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> <VRTRasterBand dataType="UInt16" band="1"></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> <ComplexSource></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> <SourceFilename relativeToVRT="1">T35TMK_20230520T090559_B02_10m.jp2</SourceFilename></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> <SourceBand>1</SourceBand></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> <SourceProperties RasterXSize="10980" RasterYSize="10980" DataType="UInt16" BlockXSize="1024" BlockYSize="1024" /></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> <SrcRect xOff="0" yOff="0" xSize="10980" ySize="10980" /></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> <DstRect xOff="0" yOff="0" xSize="10980" ySize="10980" /></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> </ComplexSource></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"> </VRTRasterBand></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span class="font"><span style="font-family:"Menlo",serif"></VRTDataset></span></span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
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<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt" id="qt">
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<p class="MsoNormal"><span style="font-family:"Arial",sans-serif">Otherwise it will use SimpleSource. There is a performance hit in using ComplexSource when it is not needed. In 3.8, there has been an optimization to improve ComplexSource performance in common
nodata-only scenarios: cf <a href="https://github.com/OSGeo/gdal/commit/cd67491d3909f5f05160fa209609b38d973c42de">
https://github.com/OSGeo/gdal/commit/cd67491d3909f5f05160fa209609b38d973c42de</a><o:p></o:p></span></p>
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</blockquote>
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<p class="MsoNormal"><span style="font-family:"Arial",sans-serif">Oh, that's great!<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial",sans-serif">PS: are there good reasons for not allowing
</span><span class="font"><span style="font-family:"Menlo",serif">-separate</span></span><span style="font-family:"Arial",sans-serif"> for multi-band inputs (by including all bands) or propagating the input block size if it's the same for all of them?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial",sans-serif">Laurentiu<o:p></o:p></span></p>
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