[Marble-devel] Map Layer Plugin for Marble

[Andrew Manson]

Hey all,

I'm just sending the list a quick message to try and get a bit of 
discussion going on the idea of applying a QGraphicsScene and a 
QGraphicsView to marble. The reason that I'm looking into this now is 
because I've been working on a simple Open Street Map rendering ( and 
editing ) program that i reckon should be easily integrated into marble.

The original way that i was thinking of doing it was using the current 
GeoData parser and other GeoData classes to import the OSM data. I gave 
it a go but i ran into a few problems with this approach, eventually 
coming to the conclusion that it would actually possibly require editing 
the parsing system to correctly parse an OSM XML document. This just 
made it more effort than it was worth. ( if you're interested or want to 
make any comments on my views on the parsing system have a look at my 
blog http://realate.blogspot.com/ )

So whats the alternative solution. My current implementation of my own 
OSM data parser and Renderer is a pure QGraphicsScene and QGraphicsView 
implementation. So i wondered, why can't i just draw this on top of 
marble? Well i reckoned that it wouldn't be such a difficult problem to 
draw my QGraphicsView that represents OSM data on top of the Marble 
Widget, and if the QGraphicsView had a fully transparent background then 
it would be a seamless integration. The only difficulty would be 
integrating the movement of the overlaid layer and the marble widget and 
then making the overlay system work for the spherical projections.

So what I'm proposing is that i work on this kind of system for a while, 
if anyone has any suggestions please let me know because I'd like this 
to be discussed fully. Also, to keep it all separate from the actual 
marble code i will try and make this whole system work as a marble 
plugin, hopefully also providing a simple way for third parties to come 
an make a rendering layer on top of marble.

- Andrew.