+1 on metatiles. I've generally found an extra 128px buffer surrounding the metatile to be sufficient for good label coverage. Your metatile size should be as large as your rendering machine can comfortably handle without running out of physical RAM, but no larger. On the EC2 machine with 512MB of RAM where I do most of my mapnik + OSM work, I've found 8x8 metatiles to work reasonably well, so that each individual mapnik render ends up being 2304x2304 pixels, subsequently cut up into 64 individual 256x256 tiles with the outer 128px buffer discarded. Only about 20% of the total rendered pixels are discarded.
For 64x64 tiles, I'd still start by rendering a 2304x2304 image, discard the outer 128px buffer, and end up with 1024 individual tiles per render. TileCache generally handles all of this for you transparently. -mike. On Dec 23, 2008, at 10:34 AM, Jay Douillard wrote: > Matthew, > > Look into metatiles > http://geowebcache.org/trac/wiki/metatiles > > Which you can use tileCache to create with mapnik. > > Pretty much the only way to get good labels that I've found. > jay > > ----- Original Message ----- > From: "Matthew Rushton" <[email protected]> > To: [email protected] > Sent: Tuesday, December 23, 2008 8:10:45 AM GMT -08:00 US/Canada > Pacific > Subject: [Mapnik-users] normal label rendering? > > Hi, > I'm using mapnik (it's great!) with open street map to render > 64x64 tiles. The problem I'm bumping up against is labels that span > tiles which in some cases are not being rendered which produces half > labels on my map. I realize that for 64x64 tiles the tiles I need to > render must be larger for this exact problem and this makes sense. > However to get labels to properly render without getting cut off I > need to render 512x512 tiles. This is very expensive and seems > really wasteful, given the entire label in all cases would be inside > a much smaller tile. My question before I go searching through code > is, is this normal? What kind of buffer is needed to properly render > tiles. Any insight into this would be great! Thanks so much. > -Matt > > > _______________________________________________ Mapnik-users mailing > list [email protected] > https://lists.berlios.de/mailman/listinfo/mapnik-users > _______________________________________________ > Mapnik-users mailing list > [email protected] > https://lists.berlios.de/mailman/listinfo/mapnik-users ---------------------------------------------------------------- michal migurski- [email protected] 415.558.1610 _______________________________________________ Mapnik-users mailing list [email protected] https://lists.berlios.de/mailman/listinfo/mapnik-users
