Hi,
I am again working on an algorithm for splitter that detects all incomplete ways and rels. It works fine with input like finland.osm.pbf (~100MB) and -Xmx1000M, but it probably would fail to process europe on a 32bit machine. Up to now, we use the overlap value to reduce the likelyhood of incomplete ways and rels. Now, I wonder what exactly splitter should do with a way that has only points in this overlap. To make it easier, let's assume that this way is not a member of a relation. Is such a way used in mkgmap or is completely ignored?
AFAIK yes - it's completely ignored.
If it is completely ignored, I think splitter should not to write it, else it should try to write it with all nodes.
Yes, that would be great. It would avoid a lot of problems with incomplete multipolygons.
In other words: If splitter could make sure that every way and relation that a) has a node within the real bbox b) may enclose the real bbox c) may cross the real bbox is written to the tile with all related elements (nodes of ways, members of relations), would we still need the overlap?
I think the overlap is superfluous if splitter can guarantee a) to c). If splitter can handle a) to c) you will have the complete country boundaries in each tile. Not a problem for Luxembourg but maybe in Russia, Canada or similar big states it will blow up each tile. Maybe this growth is worthy to check once during your development.
I remember an algorithm in mkgmap that searches the nearest city. Would this algorithm "see" a city that is in the overlap ?
No, this algorithm runs after all elements have been cut to the bbox.
ciao, Gerd
If you manage to implement that you will solve a long outstanding problem of splitter/mkgmap so I cross my fingers that you are successful! WanMil