PostGIS
Name
ST_Volume — Computes the volume of a 3D solid. If applied to surface (even closed) geometries will return 0.
Description
Availability: 2.2.0
This
method needs SFCGAL backend.
This
function supports 3d and will not drop the z-index.
This
function supports Polyhedral surfaces.
This
function supports Triangles and Triangulated Irregular Network Surfaces
(TIN).
This
method implements the SQL/MM specification.
SQL-MM IEC 13249-3: 9.1 (same as ST_3DVolume)
Example
When closed surfaces are created with WKT, they are treated as areal rather than solid. To make them solid, you need to use ST_MakeSolid. Areal geometries have no volume. Here is an example to demonstrate.
SELECT ST_Volume(geom) As cube_surface_vol,
ST_Volume(ST_MakeSolid(geom)) As solid_surface_vol
FROM (SELECT 'POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)),
((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)),
((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'::geometry) As f(geom);
cube_surface_vol | solid_surface_vol
------------------+-------------------
0 | 1