I think I'd make a_table.geom be of type Geometry rather than Polygon, then after calculating the ConcaveHulls check the geometry types and modify those ones that are not polygons.
You can use st_buffer to turn a point or a line into a polygon. David _______________________________________________ postgis-users mailing list postgis-users@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/postgis-users
