A Look at PgRouting find_ node_by_nearest_link_within_distance

The function with the glorious name “find_node_by_nearest_link_within_distance” is part of pgRouting and can be found in matching.sql.

“This function finds nearest node as a source or target of the nearest link”
That means that we can use this function e.g. to find the best road network node for a given address.

The function returns an object of type link_point:

CREATE TYPE link_point AS (id integer, name varchar);

To access only the id value of the nearest node, you can use:

SELECT id(foo.x) 
FROM (
   SELECT find_node_by_nearest_link_within_distance(
	'POINT(14.111 47.911)',
	0.5,
	'nw_table')::link_point as x
) AS foo