[gdal-dev] Make gdal_polygonize to support the mask band

[Rahkonen Jukka (MML)]

Hi,

Once again someone wants to get the footprints of valid data in images http://gis.stackexchange.com/questions/216624/creating-a-shapefile-for-footprint-of-tasters-valid-data-areas-with-gdal.

A year ago, in here https://lists.osgeo.org/pipermail/gdal-dev/2015-October/042859.html
Even suggested to create a mask-only image with 
gdal_translate in.tif mask.tif -b mask
and then polygonize that into vectors with gdal_polygonize.

I wonder how hard it would be to make gdal_polygonize to find the mask band directly and recognize it with "-b mask" just like gdal_translate does.

-Jukka Rahkonen-