mapnik/mapnik — pull request #2555 by stephend (2014-10-31 04:11:23+00:00)
Title: throw datasource_exception on GDAL RasterIO failures

Trying to read from a VRT that refers to a raster file that doesn't exist or cannot be read currently returns null data instead of throwing an exception.

Changes gdal_featureset to check return values from RasterIO and throw a datasource_exception if it fails.