Hi Thank yuo for replying me; maybe I was not too much clear so pardon me :) I'll try to explain better our concern
Regarding to the import phase (read and OSM file and create nodes and relationships on neo4j), we already did it. Actually we can read and OSM file and create a graph on neo4j; sure from the OSM we "take" only the necessary data (e.g. ways and directions of the ways) and from these necessary data we create our graph. It's a slow process (on my laptop a 2GB OSM file is loaded in around 15 hours by correctly settings memory heap both on JVM side and neo4j side). To read the OSM file we used osmosis What is scaring us is the route calculation performances. In fact we are worried if the neo4 implementation of dijkstra and/or A* can guarantee good performances when we want to calcote the shortest path between 2 points in the graph. Otherwise...should we use other algorithms like bidirectional dijkstra or contraction hierarchy? If we should use other algorithms....is there any implementation under neo4j? Thank you Angelo Il giorno venerdì 10 gennaio 2014 09:34:08 UTC+1, Angelo Immediata ha scritto: > > Hi there > > I'm using this environment: > > - spring 3.2.6 > - spring-data-neo4j 2.3.3 (I'm thinking to upgrade to the version 3 in > order to have support for neo4j 2.0) > - neo4j 1.9.5 > > > I'm thinking to use neo4j in order to store our own graph that will be > used in a route planner project. The first question is if this seems to you > (sure more experts than me) a good solution in order to build a very good > and efficient and performant route planner > Moreover as far as I know (by reading this link > http://docs.neo4j.org/chunked/1.9.5/graph-algo.html ) in neo4j these > algorithms are implemented: > > - Shortest paths > - all paths > - all simple paths > - Dijkstra > - A* > > > By reading this link > http://docs.neo4j.org/chunked/1.9.5/rest-api-graph-algos.html I saw that > REST API allows to call these algorithms: > > - Find all shortest paths > - Find one of the shortest paths between nodes > - Execute a Dijkstra algorithm with similar weights on relationships > - Execute a Dijkstra algorithm with weights on relationships > > > The second question is: can't I invoke the A* algorithm by REST API? This > is related to the fact that I'ld love to have one (ore more) dedicated > machine to neo4j and access to them by REST API (is this a good solution?) > > The last question regards neo4j performance. In my real scenario i may > import an OSM file of an whole italian region (maybe also the full Italy); > in the case of one region I can have around 10 millions of nodes (also more > than 10 million) and some millions of relationship. In this case...what are > performances with the built-in algorithms Dijkstra and/or A* when i want > the shortest path (or all paths) between two points located at the end of > the graph? > > Thank you > Angelo > -- You received this message because you are subscribed to the Google Groups "Neo4j" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
