gdal.py: Datasets deal with ESRI Web Mercator projections properly.
gdal.py: Datasets deal with ESRI Web Mercator projections properly.

If the Dataset's projection isn't recognisable by OSR, try to determine its
EPSG code, try to identify an equivalent ESRI code instead. If it succeeds,
the SpatialReference returned will be based on a EPSG one.

ecometrica/gdal2mbtiles