Re: [OSM-talk] Finding relation members in osm2pgsql PostGIS database?
2010/6/21 Phil! Gold : > I've got a PostGIS database created and maintained with osm2pgsql. For > some of the Mapnik rendering I'm doing, I'd like to see whether ways > belong to relations. (Specifically, whether a highway=* way is a member > of a route=road relation.) I've been able to look in the planet_osm_rels > table for relation membership, but the members are stored in an array, and > searching those arrays for membership, even on a bbox-restricted subset, > is really slow. Is there any way to do this faster? If not, I suppose I was playing around with representing ways as arrays of node id:s the other day, and I got seemingly decent performance, at least doing array intersection tests (using '&&', stuff like "what other ways share nodes with this way"), by building a GIN index on the array column. I was just playing around with it interactively though, so it might still be too slow for heavy use. Just mentioning it in case you have not tried. :-) -- Ture ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Finding relation members in osm2pgsql PostGIS database?
On 22 June 2010 01:15, Phil! Gold wrote: > I've got a PostGIS database created and maintained with osm2pgsql. For > some of the Mapnik rendering I'm doing, I'd like to see whether ways > belong to relations. (Specifically, whether a highway=* way is a member > of a route=road relation.) I've been able to look in the planet_osm_rels > table for relation membership, but the members are stored in an array, and > searching those arrays for membership, even on a bbox-restricted subset, > is really slow. Is there any way to do this faster? If not, I suppose I > can file a feature request against osm2pgsql for an indexed relation > membership table. osm2pgsql probably isn't the best tool for the job, relations get stored as geometries in the database, rather than meta information cross referencing the ways. What you are after is a database structure similar/the same as the main OSM DB to be able to do this kind of interrogation rather than trying to interrogated pre-processed information which has lost some/a lot of non-desirable attributes to make rendering faster. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
[OSM-talk] Finding relation members in osm2pgsql PostGIS database?
I've got a PostGIS database created and maintained with osm2pgsql. For some of the Mapnik rendering I'm doing, I'd like to see whether ways belong to relations. (Specifically, whether a highway=* way is a member of a route=road relation.) I've been able to look in the planet_osm_rels table for relation membership, but the members are stored in an array, and searching those arrays for membership, even on a bbox-restricted subset, is really slow. Is there any way to do this faster? If not, I suppose I can file a feature request against osm2pgsql for an indexed relation membership table. -- ...computer contrarian of the first order... / http://aperiodic.net/phil/ PGP: 026A27F2 print: D200 5BDB FC4B B24A 9248 9F7A 4322 2D22 026A 27F2 --- -- Last Rule of Politics: Kingdoms are good. Empires are evil. -- Console Role Playing Game Clichés, item 74 --- -- ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
