I'm working in Postgres 9.5. I have two tables, each with a column
I want to creat a single MultiPolygon that is the union of every polygon in the two tables.
I have tried running
ST_Union, but it isn't doing quite what I expected. If I do this:
SELECT ST_GeometryType(ST_Union(table1.geom, table2.geom)) FROM table1, table2;
This produces lots of
MultiPolygon results, instead of a single one, which suggests to me that the result of a simple
ST_Union is not a single polygon.
ST_Union(table1.geom, table2.geom) actually giving me, conceptually? Why are there multiple polygons?
What do I need to do to get a single multipolygon - something like