fetchSDA_spatial(): add geom.src='mlrapolygon' for querying MLRA boundaries by MLRARSYM
currently mlrapolygon is not a SSURGO table, but the official ZIP file can be queried directly via GDAL using MLRARSYM as the query attribute
in the future, if SDA ever provides MLRA geometry, the GDAL /vsizip/ method will be replaced with a T-SQL equivalent (and full support for other agg methods wil be added)
fetchSDA_spatial(): addgeom.src='mlrapolygon'for querying MLRA boundaries by MLRARSYMmlrapolygonis not a SSURGO table, but the official ZIP file can be queried directly via GDAL using MLRARSYM as the query attributeTODO:
"_ogr_geometry_"column =>"geometry""geom"