## Name

GetNodeByPoint — Finds the node-id of a node at a point location.

## Synopsis

`integer `**GetNodeByPoint**(

varchar `atopology`, geometry `apoint`, float8 `tol1``)`

;

## Description

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.

| |
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If tolerance = 0, the function uses ST_Intersects otherwise uses ST_DWithin. |

Performed by the GEOS module.

Availability: 2.0.0

## Examples

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;
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