[gdal-dev] Reading a VRT file & overview usage

Even Rouault even.rouault at spatialys.com
Wed Nov 4 07:04:37 PST 2020


Angus,

The difference of behaviour between my test case and yours is that yours has a 
<NoDataValue> set on the VRTRasterBand, and the source COGs don't have that 
value. In this situation a key optimization used by the VRT driver is 
disabled, and there's a fallback to code that won't make use of the source 
overviews to get correct results. I imagine that could be improved, but this 
is not a 5-minute type of fix. A workaround would probably to create your COGs 
with 0 set as nodata value.

Even


-- 
Spatialys - Geospatial professional services
http://www.spatialys.com


More information about the gdal-dev mailing list