Hi Frederik, > I read that I can run GraphHopper with or without CH.
this is true. Currently you have the choice between A*/Dijkstra (simple, bidirectional, bidirectional CH) > or is the speed profile baked into the routing graph The online demo is CH based and requires 3*16GB. If you'd use a none-CH graph you would have all the flexibility BUT as you already said you have to take care that the shortest path tree won't eat all the available RAM (e.g. use a memory bound dijkstra). Or you'll have to make compromises in the quality/'exactness' of the routes. With graphhopper you have the choice. If you only need a rather smallish area like bavaria (or even germany can work with tuning) you don't need CH. All that was said under the fact that you are using the in-memory data access method of graphhopper. But you can try graphhopper via a memory mapped data access which is the default for Android and you won't need lots of RAM which could be want you want for the CH-based stuff and multiple profiles. But of course this will slow things down too, but I don't know how much (will still depend on how many RAM is available). Regards, Peter. > Hi, > > On 23.07.2013 09:22, Peter K wrote: >> yesterday we released the first public version of our fast and Open >> Source routing engine called GraphHopper. > > I'd like to understand better where this fits in between the purely A* > gosmore and the CH-based osrm. > > With osrm, it is difficult to have multiple routing profiles on one > machine because you have do compile a routing graph for each profile - > a world-wide setup for "car, bike, foot" would take something like 150 > GB of memory on the server. > > With gosmore, this is easy since you only need one routing graph to > support a multitude of profiles - not only car, bike, foot, but also > motorcycle, HGV, and others. This flexibility comes at a noticeable > speed penalty. > > I read that I can run GraphHopper with or without CH. Does that mean > that when I run it without, I get the gosmore-like flexibility to > evaluate edges at runtime, or is the speed profile baked into the > routing graph (and therefore your demo server needs something like 64 > GB of RAM because it has three routing graphs)? > > Bye > Frederik > _______________________________________________ dev mailing list dev@openstreetmap.org http://lists.openstreetmap.org/listinfo/dev