설명

Retrieves the id of a node at a point location.

The function returns an integer (id-node) given a topology, a POINT and a tolerance. If tolerance = 0 means exact intersection, otherwise retrieves the node from an interval.

If apoint doesn't intersect a node, returns 0 (zero).

If use tolerance > 0 and there is more than one node near the point then an exception is thrown.

	이 함수는 tolerance = 0일 경우 ST_Intersects를, 그렇지 않을 경우 ST_DWithin을 이용합니다.

GEOS 모듈로 실행

2.0.0 버전부터 사용할 수 있습니다.

예시

다음 예시들은 AddEdge 에서 생성한 경계선들을 사용합니다.

SELECT topology.GetNodeByPoint('ma_topo',geom, 1) As nearnode
 FROM ST_GeomFromEWKT('SRID=26986;POINT(227591.9 893900.4)') As geom;
  nearnode
----------
        2
 

SELECT topology.GetNodeByPoint('ma_topo',geom, 1000) As too_much_tolerance
 FROM ST_GeomFromEWKT('SRID=26986;POINT(227591.9 893900.4)') As geom;

 ----get error--
 ERROR:  Two or more nodes found
 

참고

AddEdge, GetEdgeByPoint, GetFaceByPoint