How to use the pgRouting TSP function?

Question

For more than two days I'm trying to make the TSP algorithm work in PostgreSQL/PostGIS. My problem seems to occur when I'm trying to take into account the road network for TSP algorithm. I know that the algorithm it will calculate the distance in Euclidean space as a default setting.

As an example:

SELECT vertex_id
FROM tsp('SELECT id as source_id, lon AS x, lat AS y 
          FROM point_layer','23,221,63,432,335,',63);

where the point_layer is the table which holds the points information (as PlaceMarks), numbers like: 23,221,63,432,335 stands for places (cities) and 63 as a starting point.

If you have experience with this approach please advise.

Answer 1

According to the examples and the documentation, you should only be loading the five nodes you are interested in in the select query, so I added a where clause to your select query. You also had a trailing comma, following the list of ids in parameter two that I removed.

So give this a try and see if it works better:

SELECT vertex_id
FROM tsp('SELECT id as source_id, lon AS x, lat AS y 
          FROM point_layer where id in (23,221,63,432,335)','23,221,63,432,335',63);

Here is a link to the doc: http://pgrouting.org/docs/1.x/tsp.html