[Marble-devel] OpenStreetMap support

[Torsten Rahn]

On Sunday 13 April 2008 16:48:05 Jens-Michael Hoffmann wrote:
> > A2.) Reuse the tileset that OSM is publically offering: This would
> > require to introduce an interface for alternative TileLoader classes. The
> > tile loader for OSM would need to "translate" the lat/lon position
> > requested into OSM tile positions and would download the tiles needed and
> > would possibly need to get reprojected (depending on which approach would
> > be taken in detail).
>
> This is the approach I would prefer for the short term because I think it
> fits quite good in the existing infrastructure regarding both marble and
> OpenStreetMap.

Yes, I agree.  Tell me, if you need help or any input. :-)

> Do you think it is really faster if marble renders the data itself? Do you
> have got some numbers?

Yes, because for rendering of textures Marble needs to create a whole new 
QImage for every single frame. And it needs to transfer that QImage onto the 
graphics card each time.

When drawing polygons onto the widget directly this can be avoided. Just try 
the "Plain Map" compared to the "Atlas View" and you might get the idea of 
the difference in terms of performance. 

But of course approach A2 will be a whole lot easier to implement. And it 
would also help to render data from other established sources (like LandSat / 
WMS tiles) where there's no vector data available. So it's something we will 
still need to have even once we would have completed approach B1 late this 
year. 

Best Regards,

Torsten


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