Mapfactor Greece routing problem
  • Vote Up0Vote Down Gabriel29Gabriel29
    Hi, I have a couple maps on my phone. Hungary, Serbia, Macedonia, Greece. If i give a greek ctiy as destination, "rounting not found" Why? Hungary is ok, serbia is ok, and Hungary is ok too. We'D like to go to Greece next week, but we cant use mapfactor cause of this problem. What sould i do?
  • 6 Comments sorted by
  • Vote Up0Vote Down tomastomas
    please provide departure and destination in coordinates
  • Vote Up0Vote Down Gabriel29Gabriel29

    Hungary, Miskolc 48°06′15″N 20°47′30″E
    Greece, Sarti,40° 6' 0" North, 23° 59' 0" East

  • Vote Up0Vote Down hvdwolfhvdwolf
    This is identical to to this post
    You need to download Kosovo
  • Vote Up0Vote Down Gabriel29Gabriel29
    Kosovo? Why? Serbia, and Maceodnia are totally enough to reach Greece. Should i go through in Kosovo? :O
  • Vote Up0Vote Down hvdwolfhvdwolf
    These are all assumptions.
    I think this is a bug or implementation decision in Navigator somewhere in the shortest path algorithm. Navigator is extremely fast in route calculation. It can only do that if it uses some A* algorithm with relatively high heuristic coefficient of at least 1.3 (I think) combined with a cutoff function that removes nodes/paths that do not provide better results. This makes navigator so fast and it is also a reason why navigator needs so little memory to calculate routes (I did comparisons on memory usage, accuracy and performance between at least 6 Nav apps).

    A big disadvantage of this method is that when Navigator calculates an optimal route going "in the direction of Kosovo", and at the same time throws out less optimal routes, also out of memory, it gets stuck at the Kosovo border. And it can't "go back" in its matrix to calculate a (less optimal) route around Kosovo as it has thrown out these paths/nodes.
    Other Nav apps like OsmAnd and others keep the matrix in memory. If OsmAnd gets stuck at the Kosovo border, it simply "goes back in its tracks" and continues the calculation via one of the other less optimal routes around Kosovo. This at the same time makes memory use of OsmAnd huge compared to Navigator. (I used to be heavily involved with OsmAnd and as it's Open Source you can see in the code what it does)

    Again these are assumptions, as I don't have insight in navigators routing algorithm :). I tried to explain it in a "non-mathematical" way. There are so many implementations of A*. There is a lot to find about it on the web.

    One of the Devs of Mapfactor could probably (hopefully) confirm my explanation, or explain it better if I'm wrong.
  • Vote Up0Vote Down hvdwolfhvdwolf
    And practical and short: Add a waypoint "somewhere" in Macedonia to force Navigator to calculate a route around Kosovo if you don't want to cross Kosovo.
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