data (#23) - without GIS (#330) - Message List

without GIS

Hi all. I was wondering if there is somebody who could give me a hint with my issue here. I need to calculate the shortes way between to point which are located in two different countries. If have the distances between lets say budapest to various border-points situated at the border of hungary. I have also all the distances of its neighbouring countries from border to border. My destination is lets say paris. So the shortest path would possibly be, budapest to the austrian border to german border to french border to paris. I have all this distances but no coordinates. I there a way to solve this problem by using one of the algorithms?

williamwallace
01/30/10 00:38:22 (10 months ago)
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  • Message #1370

    Yes, you can.

    The Dijkstra doesn't need coordinates. It only cares about "costs" between two points. In your case the distance is your cost attribute.

    But what you need to know is how your points are connected, so you need a network with relations between points. If you have this, you can use pgRouting.

    daniel
    01/30/10 03:12:20 (10 months ago)
    • Message #1371

      Thanks daniel.. Let's see if i am able to get it to work..

      williamwallace
      01/30/10 03:43:14 (10 months ago)
      • Message #1372

        If something doesn't work, post your qestion here or in the mailing list.

        daniel
        01/30/10 03:45:37 (10 months ago)
        • Message #1374

          Thank You very much.. it works! the only thing i have to figure out is get the right order of the results since there is no output which gives me the right sequence... there are only vertex_id, edge_id and cost and the various steps are not in the right order...

          williamwallace
          01/31/10 03:30:56 (10 months ago)
          • Message #1375

            Do you use the trunk version of SVN? Or a Windows binary?

            As far as I remember, there should be also an "id" attribute you can order by, which it does if you use the available wrapper functions. And I guess you won't, because they all contain geometry attribute, which you don't have.
            (I'm not sure the 'id' attribute is in 1.03)

            daniel
            01/31/10 07:51:51 (10 months ago)
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