Name
GetNodeByPoint — Finds the node-id of a node at a point location.
Synopsis
bigint GetNodeByPoint(varchar atopology, geometry apoint, float8 tol1);
Descrizione
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.
![[Note]](../images/note.png)
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If tolerance = 0, the function uses ST_Intersects otherwise uses ST_DWithin. |
Eseguito dal modulo GEOS.
Disponibilità: 2.0.0
Esempi
These examples use edges we created in AddEdge
SELECT topology.GetNodeByPoint('ma_topo', geom, 1) As nearnode
FROM ST_GeomFromEWKT('SRID=26986;POINT(227591.9 893900.4)') As geom;
2
This query errors because the tolerance matches two or more nodes.
SELECT topology.GetNodeByPoint('ma_topo', geom, 1000) As too_much_tolerance
FROM ST_GeomFromEWKT('SRID=26986;POINT(227591.9 893900.4)') As geom;
ERROR: Two or more nodes found