Martijn, That's great for "zoom level 17" tiles where you always want to display everything in the bounding box.
For "zoom level 11" (for example), there are probably millions of nodes in the tile, and you can't map them all (most are too unimportant to be mapped). By using QuadTiles, you only have to look at 120,000 nodes (10,000 nodes each for the QuadTile and all of its parents) to determine what to map. Of course, you could use this in conjunction with spatial indexing to make things even faster. This scales well: the number of nodes you look at to render a "zoom level 11" tile remains constant at 120,000 (or less if the tile and its parents are fairly blank). Note: at Andy Allan's suggestion, I've moving this thread from 'newbies' to 'dev' (dev folks, please see the newbies archive for the first part of this thread). This message is cc'd to both lists, but future messages will go just to the 'dev' list. Sorry about the confusion. -- We're just a Bunch Of Regular Guys, a collective group that's trying to understand and assimilate technology. We feel that resistance to new ideas and technology is unwise and ultimately futile. On 12/25/07, Martijn van Oosterhout <[EMAIL PROTECTED]> wrote: > On Dec 25, 2007 7:31 PM, Kelly Jones <[EMAIL PROTECTED]> wrote: > > I thought the osm.xml imposed a partial ordering on nodes, not a > > complete ordering? > > I'm not sure why we need anything with quadtiles. Mapnik uses spatial > indexes so it has a complete list of every node in the given area very > cheaply. The osm.xml imposes a total order, so it renders them in the > order specified... > > Have a nice day, > -- > Martijn van Oosterhout <[EMAIL PROTECTED]> http://svana.org/kleptog/ _______________________________________________ newbies mailing list [email protected] http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/newbies
