Using ST_Extrude in PostgreSQL with PostGIS?

Question

I'm trying to use the function ST_Extrude() in Postgres 9.2. I enabled the PostGIS 2.2.0 extension and the PostGIS_SFCGAL extension (which carries the ST_Extrude function).

I can see the function in my list of functions (see snapshot), but I cannot use it.

When I try following SQL code:

CREATE TABLE house AS
SELECT id, ST_Extrude(geog, 0, 0, 5) as geom
FROM houses
WHERE id = 1500;

I get an error that the function ST_Extrude does not exist:

Does someone know what is going wrong here?

Answer 1

ST_Extrude is only supported for geometry type. From the error looks like you are trying to use it for geography. You'll probably also want to maybe change your projection to a meter based one to make sense when you extrude.

Try something like :

CREATE TABLE house AS
  SELECT id, 
      ST_Extrude(ST_Transform(geog::geometry,900913), 0, 0, 5) as geom
  FROM houses
  WHERE id = 1500;