> > http://wiki.openstreetmap.org/wiki/OSM_Server_Side_Script > > that sounds cool. Did not know it before. It's not advertised a lot ;) > What are the limits? Frederik mentioned a query against a polygon might > be slow. Which area could be returned? Only a city? Bavaria? France?
The query against a polygon is in general not very expensive. Retrieving a single polygon takes a single hard disk hit, and the computational effort can be neglected against that. The limiting factor is the RAM size of the server (4 GB). To avoid congestions, I've set a weighted limit of 10'000'000 elements so far (this takes about 500 MB of RAM to process the data, so four queries and the update process could safely run in parallel) - think of roughly 5'000'000 nodes. The amount of RAM is needed to sort the nodes, ways and relations in ascending order of their ids. Bavaria would be a corner case and is worth a try ... It doesn't work, it has already over 10 million nodes. > Or maybe only query the nodes near the border against the expensive > polygon? Whatever system you use, it will probably automatically use less a expensive query deep inside a polygon. Cheers, Roland _______________________________________________ dev mailing list dev@openstreetmap.org http://lists.openstreetmap.org/listinfo/dev
