Hi all, I'm working on a script to expire tiles bases on (daily) diffs. This so we can re-render the tiles with changes and keep the tiles without for a longer period of time. Which will allow us to have more up to date maps. And not have the server do more work than necessary since tiles that have no changes do not have to be re-renderd.
This is easily done for nodes since they contain Lon/Lat tags. So for zoom a till b the tiles can be calculated and removed. However the problem starts when ways are parsed. Since ways only contain refs to nodes. So no Lat/Lon info is provided. The average daily diff contains > 700.000 node refs in way tags. I have tried to get all the nodes (1000 nodes at the same time) from the OSM-API. This solution provided me straight away with the Lon/Lat for the nodes. However this took a very very long time. And it is not very nice to do that on a daily basis. (also for the load on the server). An other solution I tried was running a local copy of the database. running oms2pgsql in slim-mode. However this took a long time. And when running the query (with >700.000 nodes) also took a very very long time. Now of course the Lat/Lon have to be parsed but that is not the problem. As you might have guessed both solutions do not work. Or at least not good enough for my taste. I would like a simple (or at least fast) solution. I think that adding the Lat/Lon tag to node references in the ways is not an option since it would require a huge amount of queries on the database when creating the diffs. The positive side of this would that it would only have to be done once. Something else would be to have some sort of bounding box tag at the ways. This is not optimal in tile expiring but is better than it is done now. Anybody with idea's on this matter? Greetings, Roeland _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/listinfo/dev
