[gdal-dev] gdal2tiles.py of transparent background vrt/png gives black background tiles

John W. Glendening glendening at drjack.net
Mon Apr 24 22:51:18 PDT 2017

Certainly.  And I again want to thank you for your help. The files
totaled 13MB so I've put them on the web at
http://bigsurtrailmap.net/TEMP/  I will expect to delete them at some
time but not for at least a month.

The "transparent" tif was created by drawing lines on a transparent
canvas of specified size using ImageMagic convert.  The "depth8polygons"
tif was created similarly with "-depth 8" flag added and partial-opacity
polygons also drawn (outlined+filled with magenta, but they display in

Both were processed with "gdal2tiles.py -z 14
--resampling=average ...vrt"
The "transparent" file gives bad results, the "depth8polygons" one
as expected (except for the polygons being gray).

Besides the associated .vrt files I've added the .prf & .tfw files used
to create them and the gdal2tiles.py I used.  If I can help further let
me know, but unfortunately my Python coding skills are non-existent.

John Glendening

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