Union all geometry in a SQL Server table like GeomUnion in Postgres

Question

Just to clarify up-front: I\'m talking about unioning geometry, not the SQL keyword UNION.

I\'m trying to move some spatial data from Postgres with Post

Answer 1

Your best option is to create a CLR function to support the aggregate. There are a couple of existing solutions:

• Sql spatial tools
• Spatail aggregate

Answer 2

The way I ended up doing this is with variables:

DECLARE @Shape GEOMETRY
SET @Shape = GEOMETRY::STGeomFromText('GEOMETRYCOLLECTION EMPTY', @MySrid)

SELECT @Shape = @Shape.STUnion(Shape)
  FROM MyShapeTable

It's not as nice, but it works.

Answer 3

Is the UnionAggregate function SQL2012 only?

SELECT geography::UnionAggregate( geometry ) FROM some_table

Hmm guess so. http://technet.microsoft.com/en-us/library/ff929095.aspx