ST_Force3D

Introduction: Forces the geometry into a 3-dimensional model so that all output representations will have X, Y and Z coordinates. An optionally given zValue is tacked onto the geometry if the geometry is 2-dimensional. Default value of zValue is 0.0 If the given geometry is 3-dimensional, no change is performed on it. If the given geometry is empty, no change is performed on it.

Note

Example output is after calling ST_AsText() on returned geometry, which adds Z for in the WKT for 3D geometries

Format: ST_Force3D(geometry, zValue)

SQL Example:

SELECT ST_Force3D(geometry) AS geom

Input: LINESTRING(0 1, 1 2, 2 1)

Output: LINESTRING Z(0 1 0, 1 2 0, 2 1 0)

Input: POLYGON((0 0 2,0 5 2,5 0 2,0 0 2),(1 1 2,3 1 2,1 3 2,1 1 2))

Output: POLYGON Z((0 0 2,0 5 2,5 0 2,0 0 2),(1 1 2,3 1 2,1 3 2,1 1 2))

SELECT ST_Force3D(geometry, 2.3) AS geom

Input: LINESTRING(0 1, 1 2, 2 1)

Output: LINESTRING Z(0 1 2.3, 1 2 2.3, 2 1 2.3)

Input: POLYGON((0 0 2,0 5 2,5 0 2,0 0 2),(1 1 2,3 1 2,1 3 2,1 1 2))

Output: POLYGON Z((0 0 2,0 5 2,5 0 2,0 0 2),(1 1 2,3 1 2,1 3 2,1 1 2))

Input: LINESTRING EMPTY

Output: LINESTRING EMPTY