> I came across some strange behavior while panning around a VRT in QGIS. The > VRT consists of several large overlapping TIFs where some TIFs have NODATA > in areas where other TIFs have data. The behavior is hard to explain, but > it looks like the data read from the files is corrupted. Panning around, > zooming in and out, anything that triggers another read seems to change the > way the data looks. It changes colors, gets skewed, etc. The TIFs > themselves are fine on their own. > I have reduced it down to a small subset of the data which is available here > (about 2 MB): https://s3.amazonaws.com/pschmitt-test-public/data.tar.bz2 > > It consists of two TIFs: > 1.tif - fully valid > 2.tif - some valid data and some NODATA > > I also included three VRTs which I created with these commands: > gdalbuildvrt -r near near.vrt 1.tif 2.tif > gdalbuildvrt -r bilinear bilinear.vrt 1.tif 2.tif > gdalbuildvrt -r bilinear bilinear-reversed.vrt 2.tif 1.tif > > If I run this command repeatedly, the min/max of the 4 bands always come out > the same: gdal_translate -projwin 488135 4405500 488374 4405348 near.vrt > /vsistdout/ | gdalinfo -mm /vsistdin/ > Run this same command on bilinear.vrt, and the min/max change each time. So > that's weird.
For the record, the above described issue was found to be fixed per https://github.com/OSGeo/gdal/pull/1943 (available in 2.4.3) Even -- Spatialys - Geospatial professional services http://www.spatialys.com _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
