On mercredi 28 mars 2018 18:16:45 CEST Richard Greenwood wrote: > I have a question that is probably more "user" than "developer". Is there > different place that I should post my question? > > I don't think that I understand -srcnodata. I assume that -srcnodata "0 0 > 0" on a 3 band image means that all 3 bands have to be 0 to be "no data" > but I think what I'm seeing is that if any to the 3 bands is 0 then that > pixel is considered to be "no data". Am I mis-understanding -srcnodata?
Richard, That depends on the utility / algorithm. For gdalwarp, -srcnodata "0 0 0" will imply by default -wo UNIFIED_SRC_NODATA=YES See http://www.gdal.org/structGDALWarpOptions.html#a0ed77f9917bb96c7a9aabd73d4d06e08 For gdalbuilvrt / VRT (and other raster formats in general), nodata is evaluated on each band independantly. Unless you specify the NODATA_VALUES metadata item. gdalbuildvrt out.vrt in1.tif in2.tif gdal_edit.py -mo "NODATA_VALUES=0 0 0" Then utilities/algorithms that can use mask bands (not all can do however) will behave as you expect. Even -- Spatialys - Geospatial professional services http://www.spatialys.com _______________________________________________ gdal-dev mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/gdal-dev
