Hi Alexander, GraphHopper is an open source project where everything happens on your machine and a country-sized graph should fit into 1-2GB RAM. The GraphHopper Directions API is a durable, hosted GraphHopper (and other features) with multiple profiles for world wide coverage etc
Regards, Peter On 24.06.2015 12:01, Alexander Tkachov wrote: > And what is the size of such graph? > I mean, if there opportunity to download some peace of the graph? It > will improve processing time (because the graph will be in memory) and > reduce your server workload. > > Thanks a lot for the information. > > On Wed, Jun 24, 2015 at 11:44 AM, Peter <[email protected] > <mailto:[email protected]>> wrote: > > Hi Alexander, > > first, you should get yourself familiar on e.g. how a simple route > > <https://github.com/graphhopper/graphhopper/blob/master/docs/core/routing.md> > can be calculated with the default algorithms from GraphHopper. > > Then for your new algorithm you can use the low level API > > <https://github.com/graphhopper/graphhopper/blob/master/docs/core/low-level-api.md> > where you have direct access to the Graph object: > Graph graph = graphHopper.getGraph(); > > Read a bit about tower vs. pillar nodes, and try to traverse the > graph its 'junctions' and implement the algorithm for it. As an > example you can have a look into Dijkstra.java > > <https://github.com/graphhopper/graphhopper/blob/master/core/src/main/java/com/graphhopper/routing/Dijkstra.java>. > > Also read about custom weighting > > <https://github.com/graphhopper/graphhopper/blob/master/docs/core/weighting.md> > and flag encoders > > <https://github.com/graphhopper/graphhopper/blob/master/docs/core/create-new-flagencoder.md>. > > Kind Regards, > Peter > > > On 24.06.2015 11:31, Alexander Tkachov wrote: >> Hi. >> I have a problem. I want to implement my own search algorithm >> (the shortest path between two points on map for cars). For these >> purposes I need some kind of graph (or something else). If there >> opportunity to get crossroads graph? I mean, I need something, >> which contains crossroads where each crossroads contains >> coordinates, the list of nearest crossroads and distances (m or >> km) to these nearest crossroads. If there will be any other >> parameters (like speed limits etc) it will be great. >> How can I get such kind of data if on the beginning I have only >> coordinates of start and end points. >> >> Thanks. >>
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