Early this morning Curt committed my patches to add tile support for OSM to the CVS tree (thanks Curt).
Tiles are small (256x256) map sections that get assembled on-the-fly to make an image that fills the xastir window. Since typical xastir windows are larger than 256x256, there is a small penalty for the extra http requests, but a big gain in re-use. Use of tiles is the key to 'slippy map' implementations in browsers and some newer apps (take a look at TangoGPS for an example). Tiles also improve the OSM experience with xastir, just don't expect 'slippy map' performance. Xastir's strengths like in other areas. There is an new README file describing OSM that gives a lot more details on both the static and tiled maps. Please read it carefully. The default setup provides new OSM*.geo map description files. There are a mix of tiled and static maps. You can tell the difference by file name. While any of the OSM based styles could be tiled, the tiles from CloudMade require an access key. You have to register for at the CloudMade site to get a key and then modify the appropriate GEO file. The biggest weakness in the present tiling implementation is that a slow server, or worse one that does not respond, is a real problem since for large screens you could have to wait 20 or more tiles to time out before the display will refresh. The ski trail version of OSM was giving me headaches with timeouts yesterday- take care. I am working on a way to cancel the tile downloads, but since most sites are responsive I don't think you will run into too many problems (unless you are a skier - hi hi ). Tiles are separated from the standard Xastir cache so that they can be shared with other OSM applications. I have successfully shared tiles between Xastir and TangoGPS. See the README.OSM_maps file for more details. Let me know if you run into problems. 73, ...jerry KA6HLD _______________________________________________ Xastir mailing list [email protected] http://lists.xastir.org/cgi-bin/mailman/listinfo/xastir
