Does pgRouting support turn-by-turn routing?

Question

I have route list as result of pgRouting with street names. How to get messages "Turn left", "Go along" etc ... Can pgRouting do this or I need some other source and which?

Answer 1

I think this has been discussed a few times already, see:

• driving directions in pgRouting
• http://postgis.refractions.net/pipermail/postgis-users/2010-February/025967.html
• http://www.osgeo.org/pipermail/pgrouting-users/2011-October/000849.html

If you are able to translate this from Italian, you may even use the function posted here: http://lists.osgeo.org/pipermail/pgrouting-users/2011-January/000537.html

Answer 2

Do you have Edge (topology) setup in your postgis database?

Example pgRouting gives the ability to create the source-target (start-end nodes) information within PostgreSQL using assign_vertex_id():

SELECT assign_vertex_id(table_name, snapping_range, geometry_column_name, edge_id_column_name);

where table_name is the name of the edges table, nodes within snapping_range (value is in your current projection units) will be snapped, geometry_column_name is the name of the geometry column (usually ‘the_geom’), edge_id_column_name is the name of the edge id column (usually gid).

This function requires ‘source’ and ‘target’ integer fields.

ALTER TABLE ways ADD COLUMN source integer;
ALTER TABLE ways ADD COLUMN target integer;
SELECT assign_vertex_id('ways', 0.00001, 'the_geom', 'gid');

http://www.pgrouting.org/docs/howto/topology.html