Name
GetEdgeByPoint — Finds the edge-id of an edge that intersects a given point.
Synopsis
integer GetEdgeByPoint(varchar atopology, geometry apoint, float8 tol1);
Descrizione
Retrieves the id of an edge that intersects a Point.
The function returns an integer (id-edge) given a topology, a POINT and a tolerance. If tolerance = 0 then the point has to intersect the edge.
If apoint doesn't intersect an edge, returns 0 (zero).
If use tolerance > 0 and there is more than one edge 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.GetEdgeByPoint('ma_topo',geom, 1) As with1mtol, topology.GetEdgeByPoint('ma_topo',geom,0) As withnotol
FROM ST_GeomFromEWKT('SRID=26986;POINT(227622.6 893843)') As geom;
with1mtol | withnotol
-----------+-----------
2 | 0
SELECT topology.GetEdgeByPoint('ma_topo',geom, 1) As nearnode
FROM ST_GeomFromEWKT('SRID=26986;POINT(227591.9 893900.4)') As geom;
-- get error --
ERROR: Two or more edges found