box2d A box composed of x min, ymin, xmax, ymax. Often used to return the 2d enclosing box of a geometry. box2d is a spatial data type used to represent the enclosing box of a geometry or set of geometries. ST_Extent in earlier versions prior to PostGIS 1.4 would return a box2d. box3d A box composed of x min, ymin, zmin, xmax, ymax, zmax. Often used to return the 3d extent of a geometry or collection of geometries. box3d is a postgis spatial data type used to represent the enclosing box of a geometry or set of geometries. ST_Extent3D returns a box3d object. box3d_extent A box composed of x min, ymin, zmin, xmax, ymax, zmax. Often used to return the extent of a geometry. box3d_extent is a data type returned by ST_Extent. In versions prior to PostGIS 1.4, ST_Extent would return a box2d. This section lists the automatic as well as explicit casts allowed for this data type Cast To Behavior box2d automatic box3d automatic geometry automatic GEOMETRY Planar spatial data type. GEOMETRY is a fundamental postgis spatial data type used to represent a feature in the Euclidean coordinate system. GEOGRAPHY Ellipsoidal spatial data type. GEOGRAPHY is a spatial data type used to represent a feature in the round-earth coordinate system. ,