Nombre
ST_NumGeometries — Devuelve el numero de puntos en la geometría. Funciona con todas las geometrías.
Sinopsis
integer ST_NumGeometries(geometry geom);
Descripción
Returns the number of elements in a geometry collection (GEOMETRYCOLLECTION or MULTI*). For non-empty atomic geometries returns 1. For empty geometries returns 0.
Mejorado: 2.0.0 se introdujo soporte para superficies poliédricas, Triangulos y TIN.
Cambiado: 2.0.0 En versiones anteriores esto devolvería NULL si la geometría no era de tipo collection/MULTI. 2.0.0+ devuelve 1 para geometrías simples, por ejemplo, POLYGON, LINESTRING, POINT.
Changed: 3.6.0 TIN and PolyhedralSurface are treated as unitary geometries and return 1; use ST_NumPatches to count faces.
This method implements the SQL/MM specification. SQL-MM 3: 9.1.4
This function supports 3d and will not drop the z-index.
This function supports Polyhedral surfaces.
This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).
Ejemplos
This example returns 1; prior versions would have returned NULL.
SELECT ST_NumGeometries('LINESTRING(77.29 29.07,77.42 29.26,77.27 29.31,77.29 29.07)');
st_numgeometries
------------------
1
(1 row)
A MultiPoint counts as one geometry within a GeometryCollection.
SELECT ST_NumGeometries('GEOMETRYCOLLECTION(MULTIPOINT((-2 3),(-2 2)),
LINESTRING(5 5,10 10),
POLYGON((-7 4.2,-7.1 5,-7.1 4.3,-7 4.2)))');
st_numgeometries
------------------
3
(1 row)