6.1 Output functions
6.1.1 Well-known binary (WKB) and well-known text (WKT)
6.1.2 Keyhole Markup Language (KML)
6.1.3 Geography Markup Language (GML)
6.1.4 Geometry JavaScript Object Notation (GeoJSON)
6.1.5 Scalable Vector Graphics (SVG)
6.1.6 Mapbox Vector Tile (MVT) and Protocol Buffers
6.1.7 Tiny WKB (TWKB)
6.1.8 Extensible 3D Graphics (X3D)
6.1.9 Examples of output functions
6.1.10 Geohash
6.2 Constructor functions
6.2.1 Creating geometries from text and binary formats
6.2.2 ST_GeomFromText
6.2.3 ST_GeomFromWKB and ST_GeomFromEWKB
6.2.4 ST_GeomFromGML, ST_GeomFromGeoJSON, ST_GeomFromKML, ST_GeomFromTWKB, ST_GeomFromGeoHash
6.2.5 Creating geographies from text and binary formats
6.2.6 Using text or binary representations as function arguments
6.3 Accessor and setter functions
6.3.1 Spatial reference identifiers
6.3.4 Geometry type functions
6.3.5 Geometry and coordinate dimensions
6.3.6 Retrieving coordinates
6.3.7 Checking geometry validity
6.3.8 Number of points that defines a geometry
6.4 Measurement functions
6.4.1 Geometry planar measurements
6.4.2 Geodetic measurements
6.5 Decomposition functions
6.5.1 Bounding box of geometries
6.5.2 Boundaries and converting polygons to linestrings
6.5.4 Returning points defining a geometry
6.5.5 Decomposing multi-geometries and geometry collections
6.6 Composition functions
6.6.1 Making points
6.6.2 Making polygons
6.6.3 ST_MakeEnvelope
6.6.4 ST_MakePolygon
6.6.5 ST_BuildArea
6.6.6 ST_Polygonize
6.7 Simplification functions
6.7.1 Grid snapping and coordinate rounding
6.7.2 Simplification
6.8 Summary