`pgr_pointToEdgeNode`

- Converts a point to a `vertex_id`

based on closest edge.

Warning

These are proposed functions

- They are not officially of the current release.
- They likely will not be officially be part of the next release:
- The functions might not make use of ANY-INTEGER and ANY-NUMERICAL
- Name might change.
- Signature might change.
- Functionality might change.
- pgTap tests might be missing.
- Might need c/c++ coding.
- May lack documentation.
- Documentation if any might need to be rewritten.
- Documentation examples might need to be automatically generated.
- Might need a lot of feedback from the comunity.
- Might depend on a proposed function of pgRouting
- Might depend on a deprecated function of pgRouting

The function returns:

`integer`

that is the vertex id of the closest edge in the`edges`

table within the`tol`

tolerance of`pnt`

. The vertex is selected by projection the`pnt`

onto the edge and selecting which vertex is closer along the edge.

```
integer pgr_pointToEdgeNode(edges text, pnt geometry, tol float8)
```

Given an table `edges`

with a spatial index on `the_geom`

and a point geometry search for the closest edge within `tol`

distance to the edges then compute the projection of the point onto the line segment and select source or target based on whether the projected point is closer to the respective end and return the source or target value.

Parameters

The function accepts the following parameters:

edges: | `text` The name of the edge table or view. (may contain the schema name AS well). |
---|---|

pnt: | `geometry` A point geometry object in the same SRID as `edges` . |

tol: | `float8` The maximum search distance for an edge. |

Warning

If no edge is within tol distance then return -1

The `edges`

table must have the following columns:

`source`

`target`

`the_geom`

History

- Proposed in version 2.1.0

```
SELECT * FROM pgr_pointtoedgenode('edge_table', 'POINT(2 0)'::geometry, 0.02);
pgr_pointtoedgenode
---------------------
1
(1 row)
SELECT * FROM pgr_pointtoedgenode('edge_table', 'POINT(3 2)'::geometry, 0.02);
pgr_pointtoedgenode
---------------------
6
(1 row)
```

The example uses the Sample Data network.