PostGIS  2.2.7dev-r@@SVN_REVISION@@
PG_FUNCTION_INFO_V1 ( LWGEOM_perimeter2d_poly  )

find the "perimeter of a geometry" perimeter(point) = 0 perimeter(line) = 0 perimeter(polygon) = sum of ring perimeters uses euclidian 2d computation even if input is 3d