And finally I have kludged myself to a solution by using flags -type Truecolor -depth 8 in my ImageMagick TIF creation, which produces only 3 bands. Altering the vrt accordingly, and using -a 0,0,0 in pdal2tiles.py, I get the expected result. This has the effect of removing any pure black in the overlay, but that is not significant for my case.
Still, I would hope to find a cleaner solution. In particular, since in my pre-kludge case I start from a RGBA TIF and since gdal2tiles.py produces RGBA PNGs, I would have thought I could get an overlay which has a partial opacity. My original case did have one partial opacity polygon, which I removed after I learned that only a 0/1 opacity solution was possible. I can live without that, but it does surprise me that there appears no way to pass on the TIF opacity to the PNG opacity. John Glendening _______________________________________________ gdal-dev mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/gdal-dev
