Frederik Ramm wrote: > Hi, > > On 04/13/2012 11:25 AM, Paul Norman wrote: >> Something I've wondered is if it is more efficient to be generating >> these with osmosis with a planet file updated daily or with a >> pgsnapshot database updated continually? > > I have little experience with the pgsnapshot schema so cannot really > say. When we started doing the Geofabrik extracts, that schema wasn't > around and PostGIS was at release 1.3 and had really bad > point-in-polygon performance so unless you were happy with rectangular > extracts, it was impossible to run the job off a PostGIS database. > Things might have changed now and I'd love to hear from someone who > tried it.
Those who are interested in point-in-polygon performance should read this document which describes how to use a clever trick instead of raw power. http://www.gaia-gis.it/spatialite-3.0.0-BETA1/WorldBorders.pdf I had a try and splitted the most accurate Finnish municipality polygons into a chessboard like polygons and it really makes difference with PostGIS too. Recent OpenJUMP Plus version has all the tools which are needed: Create Grid tool for making the splitting layer and Polygon Overlay for cutting the original complicated polygon layer into pieces by the splitting layer. -Jukka Rahkonen- _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/listinfo/dev
