Even Rouault-2 wrote > For GeoTIFF, the unit of query remains the block. So if a block is missing > is > present, it computes how many pixels of the window of request intersect > the > block, and count them as present. > > Imagine that you have a raster of dimensions 20x20, with tiles of size > 10x10. > Imagine the first block (pixels 0,0 to 9,9) is missing. And you call > GetDataCoverageStatus() with (5,5,15,15). Then you will have a > contribution of > 10x5 valid pixels from the top-right block, 5x10 from the bottom-left > block > and 10x10 from the bottom-right block, hence a non-null percentage of 200. > / > 225. * 100 = 88.9 %
Ah ok, makes sense. Having SPARSE_OK=YES mean that gdal_translate will actually skip null blocks is a good additiona also - more intuitive. -- View this message in context: http://osgeo-org.1560.x6.nabble.com/gdal-dev-Call-for-discussion-on-RFC-63-Sparse-datasets-improvements-tp5275443p5275600.html Sent from the GDAL - Dev mailing list archive at Nabble.com. _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
