PostGIS

geometry — The type representing spatial features with planar coordinate systems.

geometry is a fundamental PostGIS spatial data type used to represent a feature in planar (Euclidean) coordinate systems.

All spatial operations on geometry use the units of the Spatial Reference System the geometry is in.

This table lists the automatic and explicit casts allowed for this data type:

Section 4.1, “Spatial Data Model”, Section 15.3, “PostGIS SQL-MM Compliant Functions”