[FOSS-GPS] GPSD, geoclue, and the geolocation service stack

[Sander van Grieken]

On Saturday 24 April 2010 12:33:48 Florian Lohoff wrote:
> On Thu, Apr 22, 2010 at 01:57:47PM -0400, Eric Raymond wrote:
> > Ideally, geoclue would work side by side with the sort of map service layer
> > people have been discussing here.  I didn't have a lot to contribute to
> > that discussion, because I don't know a lot about the map end of things.
> > But I do think it would be silly to duplicate map-service code across 
> > a dozen different projects.  I'd prefer to see a map-service project with
> > well-defined APIs that concentrated expertise about getting and caching
> > tiles in one place.

Seems reasonable. How that that API should look is not yet clear to me. Should the concept 
of tiles remain visible outside the API, or should it just prepare a pixmap of the 
requested area, or maybe both. Also a callback mechanism should be in place for signalling 
when a tile is asynchronously fetched (i.e. from the network)

> In the end wouldnt it make more sense to provide some vector interface,
> something like navit? Loading and caching tiles can consume tons of 
> flash/disk space and with todays mobile networks the software may be
> useless in rural areas across the globe.
> 
> I stopped using any tile consuming mobile application as i very often
> forgot to preseed the trip i was planning and there was no mobile coverage.

Well I very much like the tiles. I think there's a use for them besides the vector data. 
It's much less CPU intensive, there are different sets for different usecases (think 
opencyclemap) for which a vector based solution might not have a proper renderer, and 
finally, storage is cheap these days :)

From time to time I also forgot to cache an area, but that was never really a problem, 
since I could grab a set when being near a wifi spot.

The problem with vector data is that every app seems to have its own indexing mechanism, 
which stops it from being reusable.

> Yes - the tiles look much nicer but are limited to the facts the original
> renderer decided would be important. They either rely on the user preseeding
> the cache or having acceptable mobile data coverage.

I see... I see...  a smart gps app.... that peeks into my calendar.... and fetches the 
tiles for my destination.... when cheap internet is available ;)

grtz,
Sander