[Marble-devel] OpenStreetMap support

[Jens-Michael Hoffmann]

Hi Torsten,

Am Sonntag, 13. April 2008 12:08:55 schrieb Torsten Rahn:
> On Saturday 12 April 2008 23:22:08 Jens-Michael Hoffmann wrote:
> >  I would like to improve the support for OpenStreetMap, so this is where
> > I'm working at the moment.
>

> What approach did you have in mind?
>
> There are several possible approaches: And we'd like to support solution A1
> or A2 in the short term (for KDE 4.1) and solution B1.) in the mid term
> future (somewhen after KDE 4.1).

Sounds reasonable.

> 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.

> B1.) (re-)render the data live onto the widget for each frame that gets
> displayed.
>
> B2.) render the data onto the texture tiles. This would require the data to
> only get drawn onto the tiles once.
>
> Given that texture tile are Marble's most obvious performance bottleneck
> and given that approach B1.) would give us better render quality, speed and
> more flexibility (in terms of being able to select objects) we'd like to go
> for approach B1.)

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

> Any input? Suggestions? :-)

not yet :-) right now I'm going through the docs and source.

Best regards

Jens-Michael