[mkgmap-dev] Commit: r766: Write more of the *.mp-data.From Robert Vollmert rvollmert-lists at gmx.net on Thu Dec 4 15:06:41 GMT 2008
Hi Alex, thanks for your help! On Dec 4, 2008, at 13:44, Alexander Atanasov wrote: > On 12/4/08, svn commit <svn at mkgmap.org.uk> wrote: >> what it does. The road class from RouteParams is set in various >> places, not really sure they should all get the same. (Why is it > > They shouldn't be the same. Some ascii art: > > ----------------TRUNK ROAD------L---------------- > -- local neighborhood streets -| > |--- --- many small streets --- | > \ > -------L- OTHER TRUNK ROAD ---------------- > > The small streets should be class 0, TRUNKs class1, etc. > highways class 6. > >>> From the small streets you have links to L, how to get on the > next road class /i'm not sure but highway herarchies sounds like this/ Right, the streets come different classes. I'm currently writing this class in three places: NOD 2: the first byte is class and speed and two unknown bits (once per road) Table A: one byte is class and speed and oneway and toll (once per arc) Arc: the destination class (this must be wrong) For the moment, we're not writing any links. I assume well-placed links would just optimize routing, but it seems to work without. Are links only ever between nodes on the same road, or can they go further? Say A--1--B--2--C where A and B are nodes in a residential area, 1 and 2 are different small streets, and C is on a trunk road. Can there be a link A->C? >> "destination" class in an arc?) > > That's for reading. If you are on node class 5 skip nodes with > class < 5. > The graph is searched bidirectional. Start from pos and dest and try > to go to a bigger road class. At some point they meet each other. > In other words when you get on the highway stay there, don't route > along > residental streets. The class of a node is the maximum of the classes of the roads it lies on? And the destination class of an arc/link is the class of the destination node? That makes a lot of sense, but I remember seeing some maps where this didn't seem to be the case. Cheers Robert
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