On Sun, 8 Feb 2009, Roeland Douma wrote: > However I am wondering is it possible to add a range of zoom levels? Since I > probably want to erase zoom 10-18.
My method is to use osm2pgsql to generate a list of dirty tiles at my maximum zoom level (17) and then the script which actually does the expiry can generate a list of tiles for all the lower zoom levels from this information alone. e.g. if tile (x, y, 17) is expired, you know that you also need to expire (x/2, y/2, 16), (x/4, y/4, 15), (x/8, y/8, 14), etc. See: https://subversion.nexusuk.org/trac/browser/openpistemap/trunk/scripts/expire_tiles.py I'm still trying to improve the performance of the expire_tiles.py script, but the premise is that it looks on the disk to see what tiles actually exist and inserts a reference to them into a Postgres table together with a time stamp. This means that I can expire higher zoom levels more frequently than lower levels (e.g. we don't want zoom level 0 to be expired every time someone makes a change anywhere on the planet :) - Steve xmpp:[email protected] sip:[email protected] http://www.nexusuk.org/ Servatis a periculum, servatis a maleficum - Whisper, Evanescence _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/listinfo/dev
