I'm trying to make a mosaic (and then a pyramid) of historic map tiles. Every map tile has a border, I got rid of it with gdalwarp (adding an alpha band and specifying the border, as I stated here). ...
I have an RGB GeoTIFF file and I want to convert a specific RGB colour to transparent. I would like to use GDAL for doing this, but external Python scripts are also an option (though I haven't learned ...