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<p class="MsoNormal">Hi,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-US">I tried the new SQL function “gdal_get_pixel_value” from this PR
<a href="https://github.com/OSGeo/gdal/pull/6877">https://github.com/OSGeo/gdal/pull/6877</a>. It is made to query a single point at a time but with some SQL I managed to query a few points with one ogrinfo command. I think that the query works even the
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">ogrinfo -sql "SELECT gdal_get_pixel_value('P3412A.tif', 1, 'pixel', 100, 200) as p1 UNION SELECT gdal_get_pixel_value('P3412A.tif', 1, 'pixel', 100, 400) as p1 UNION SELECT gdal_get_pixel_value('P3412A.tif', 1, 'pixel',
300, 400) as p1" p3412A.gpkg --config OGR_SQLITE_ALLOW_EXTERNAL_ACCESS YES<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">INFO: Open of `p3412A.gpkg'<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> using driver `GPKG' successful.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Layer name: SELECT<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Geometry: None<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Feature Count: 3<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Layer SRS WKT:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">(unknown)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">p1: Real (0.0)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">OGRFeature(SELECT):0<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> p1 (Real) = 11.1850004196167<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">OGRFeature(SELECT):1<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> p1 (Real) = 11.7200002670288<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">OGRFeature(SELECT):2<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> p1 (Real) = 13.5690002441406<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">However, the SQL statement with UNIONs gets too long if user wants to query hundreds or points. Is there any simple trick, SQL based or other, to make such a query?<br>
The ultimate use case would be to find an alternative for the GRASS function v.drape
<a href="https://grass.osgeo.org/grass82/manuals/v.drape.html">https://grass.osgeo.org/grass82/manuals/v.drape.html</a>.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">-Jukka Rahkonen-<o:p></o:p></span></p>
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