2009/12/10 Fox Mulder <quakem...@gmx.net>: > Neil Jerram wrote: >> 2009/12/9 arne anka <openm...@ginguppin.de>: >>> not to belittle the effort -- but in what respect will it be different >>> from navit? >>> would it be worth a consideration to use navit's engine, maybe improving >>> it and add a new efl based interface? >> >> Good question. >> >> For me the frustrating thing about navit is that it doesn't share maps >> with tangogps. So: >> >> - if you do consider helping navit instead, please consider enhancing >> it to use the same maps as tangogps >> >> - if you continue with your own project, please consider making it use >> the same maps as tangogps. > > I don't think that this would be a good choice at all. > Tangogps uses png pictures with no routing information within these > files. For a navigation application you need vector images to determine > the path for routing. And the data for maybe a whole country in png and > for all zoom levels would be a few gigabyte with tens of thousands of > files. Compared to the vector format navit uses which is only a few > hundred megabytes in one file. And it could be rendered in all zoom > levels because it is in vector format. > So if something should be changed, than it should be tangogps and > allother apps that uses png files to use a vector format like navit does > which is way better for this purpose.
Thanks for following up and explaining this; what you say makes sense. I suppose I was representing the non-technical point of view: "I've already downloaded a pile of map data once, why should I need to install or download it again?" I can see now why navit can't use only tangogps's bitmap data. But I would guess that a combination could work well: bitmap data for display, plus vector data for routing. The bitmap data could be shared. It would take a lot of space per tile, but would only be needed for places visited and zoom levels used. The vector data would be needed over a much larger area, but would take much less space per square kilometer. I guess the problem then would be ensuring consistency between the vector and bitmap data... Regards, Neil _______________________________________________ Openmoko community mailing list firstname.lastname@example.org http://lists.openmoko.org/mailman/listinfo/community