Descrição

Returns the number of elements in a geometry collection (GEOMETRYCOLLECTION or MULTI*). For non-empty atomic geometries returns 1. For empty geometries returns 0.

Melhorias: 2.0.0 suporte para superfícies poliédricas, triângulos e TIN introduzido.

Alterações: 2.0.0 Em versões anteriores retornaria NULO se a geometria não fosse do tipo coleção/MULTI. 2.0.0+ agora retorna 1 para geometrias únicas ex: POLÍGONO, LINESTRING, PONTO.

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).

Exemplos

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)

Veja também

ST_GeometryN, ST_Multi