Chapter 8. SFCGAL Functions Reference

Table of Contents

SFCGAL is a C++ wrapper library around CGAL that provides advanced 2D and 3D spatial functions. For robustness, geometry coordinates have an exact rational number representation.

Installation instructions for the library can be found on the SFCGAL home page (http://www.sfcgal.org). To enable the functions use create extension postgis_sfcgal.

8.1. SFCGAL Management Functions

Abstract

This section lists functions for determining version of SFCGAL and library dependencies you are running.

8.2. SFCGAL Accessors and Setters

Abstract

These functions access or set properties of geometries. Geometries primarily supported by these functions are TINS and Polyhedral Surfaces.

  • CG_ForceLHR — Forza l'orientazione di tipo LHR
  • CG_IsPlanar — Verifica se una superficie è planare o meno.
  • CG_IsSolid — Test if the geometry is a solid. No validity check is performed.
  • CG_MakeSolid — Cast the geometry into a solid. No check is performed. To obtain a valid solid, the input geometry must be a closed Polyhedral Surface or a closed TIN.
  • CG_Orientation — Determina l'orientazione di una superficie.
  • CG_Area — Calculates the area of a geometry
  • CG_3DArea — Computes area of 3D surface geometries. Will return 0 for solids.
  • CG_Volume — Computes the volume of a 3D solid. If applied to surface (even closed) geometries will return 0.
  • ST_ForceLHR — Forza l'orientazione di tipo LHR
  • ST_IsPlanar — Verifica se una superficie è planare o meno.
  • ST_IsSolid — Test if the geometry is a solid. No validity check is performed.
  • ST_MakeSolid — Cast the geometry into a solid. No check is performed. To obtain a valid solid, the input geometry must be a closed Polyhedral Surface or a closed TIN.
  • ST_Orientation — Determina l'orientazione di una superficie.
  • ST_3DArea — Computes area of 3D surface geometries. Will return 0 for solids.
  • ST_Volume — Computes the volume of a 3D solid. If applied to surface (even closed) geometries will return 0.

8.3. SFCGAL Processing and Relationship Functions