[OSM-dev] Nearest way for a location

[Eric Marsden]

>>>>> "nd" == Nolan Darilek <nolan at thewordnerd.info> writes:

  nd> Basically, if a user reaches an intersection and turns onto a new
  nd> street, I'd like to provide feedback that he is on a new way as soon as
  nd> I can. Granted, GPS inaccuracy makes instantly doing so impossible, but
  nd> when the user is a few meters from a given intersection, I should be
  nd> able to pretty quickly establish what way he is on. Unfortunately, my
  nd> current method leaves a lot to be desired.

  This problem is called "map matching" in the literature. As you
  suggest, you can do better than looking for the nearest way if you
  take into account routing information included in the OSM data
  (highway types, oneway tags, turn restrictions, etc.)

  A student (Lukas Kabrt) is working on a similar problem (without the
  "real time" element) for OSM in the Google Summer of Code. He has some
  bibliographic references and C# code available at

     http://wiki.openstreetmap.org/wiki/Routing/Travel_Time_Analysis

  Otherwise, projects like Navit and Gosmore do this map matching (using
  simpler methods) in realtime; their source code is available. 
  
-- 
Eric Marsden