Hello Ted, It is not necessary to use Contraction Hierarchies. You can run the Dijkstra and A* algorithms from either the starting point or the ending point. And you can keep the algorithm running as long as you have unvisited end points or starting point. Since you only have 70 ending points, you can start the algorithm with them.
My Gosmore program can do A* on the complete US road network with realistic hardware and starting points can be added to the structure without starting from scratch, but that feature is not exposed as a nice interface and some coding is required. On Wed, Jul 14, 2010 at 5:20 AM, Ted Rosenbaum <[email protected]> wrote: > Hi, > I am very new at routing (this is not my field, and I am just looking to use > this in my own research). I have a general and a specific question. > First the general: > I am looking to compute something akin to driving distances along the US > road network from a large number of points (around 10,000) to a small number > of points (around 70). (This is not a traveling salesman problem--I just > need the routes between pairs). I have struggled to find an easy way to do > this. I found the OSRM project and it seems useful (as did the Contraction > Hierarchies algorithm more broadly), but I was wondering if I am missing > some simple library in R, python, postgres, or Cthat would enable me to do > this in a reasonable amount of time. I would appreciate any insights into > whether I am on the right track by using the OSRM project or if I should be > looking elsewhere. > And the specific-- > I have been trying to setup OSRM. When I run extractNetwork on an osm file, > I receive a long series of error messages that "Node 123456789 missing > albeit referenced in way. Edge skipped" (where the numbers very). Then when > running createhierarchy I get the error message "Importing n = 152702 nodes > ... and 158785 edges ...unresolved source NodeID: 152661" I've tried this > on lots of different osm files and all of them give me similar error > messages. I would appreciate any insights into whether I am doing something > wrong or whether this is a bug. > > Thanks very much. > -Ted > > --------------------------------------------------- > Graduate Student > Yale University > Department of Economics > > > _______________________________________________ > Routing mailing list > [email protected] > http://lists.openstreetmap.org/listinfo/routing > > _______________________________________________ Routing mailing list [email protected] http://lists.openstreetmap.org/listinfo/routing
