I'm seeing some errors reading reduced-resolution buffers from the alpha band of an RGBA image.
Code and link to raster to reproduce: https://gist.github.com/perrygeo/07ce04fe886d1c8090ab1b22d7579396 The original raster is 4 bands, 1223x1223. If I attempt to read a 734x734 buffer (or any smaller resolution) from the alpha band hBand = GDALGetRasterBand( hDataset, 4 ); pafScanline = (int *) CPLMalloc(sizeof(int) * 734 * 734); GDALRasterIO( hBand, GF_Read, 0, 0, 1223, 1223, pafScanline, 734, 734, GDT_Byte, 0, 0 ); I get ERROR 1: IReadBlock failed at X offset 0, Y offset 0 This DOES NOT occur if * the buffer is 735x735 or greater * reading bands 1, 2 or 3 to buffer of any size * using GDAL < 2.0, seems unaffected So far I've only reproduced on OSX but would be interested to see if Linux exhibits the same behavior. I'm curious why it there appears to be a buffer size threshold, why it only affects alpha bands and why only GDAL 2.x is affected. Before I dig in, does anyone have any theories about what's going on here? Thanks, Matt Perry _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
