I've been playing around with some OSM tile mapping in other applications (tangogps, etc). I know xastir has some OSM tile support, but it's meant for online operation.
So, I started playing around. I'm using an ubuntu VM on my macbook pro. 2.66GHz i7, 4Gb RAM, 1 processor allocated to VM. The OSM tile coordinate system is fairly straightforward. A little hacking resulted in a script that will download maps for a given rectangle and zoom level, so I can preload a map cache (for tangogps). Grab files for areas where I live, work, and play. Surprisingly, this only results in about 1.8Gb of data. Yet more hacking results in a script to generate .geo files for everything in the tangogps/OSM map cache. Now then, let's feed 'em to xastir. In case you're curious, it takes about 3 or 4 hours to index 250,000 new maps. Operations that involve "managing" maps - changes in maps selected for display, zooming, or just opening the map chooser with "expand dirs" on - can be quite slow. Like come back in 10 minutes slow. Once you get the map view you want, things are surprisingly back to normal. panning around redraws in normal time, even though at the moment I have 100,000+ tiles to chose from, plus a set of TIGER shapefiles to render on top of that. zooming is fine, too, unless I zoom far enough to change the mapset. Conclusion: using xastir pre-rendered map tiles for detailed data for a large area is not practical at this point. If you change OSM zoom levels, the penalty is just too high. Next step, see if I can shoehorn a map rendering engine, web server, and caching proxy server onto my xastir box and see if that is feasible. Or maybe I should just tweak/create some dbfawks so the shapefile lines and labels are fat enough for me to see 'em while driving. -Jason kg4wsv _______________________________________________ Xastir mailing list [email protected] http://lists.xastir.org/cgi-bin/mailman/listinfo/xastir
