[KPhotoAlbum] GPS support in KPhotoAlbum

Matthias Füssel matthias.fuessel at gmx.net
Wed Jul 22 16:26:54 CEST 2009


I'll try to structure my thoughts a bit. Here we go:

Geoposition Features I would like to see in KPA:

* select images by position: Just like you now narrow down the selection by 
category, you should also be able to say "by position", draw a rectangle on a 
map and select everything inside it.

* show map during slideshow: in a slideshow, while you are retelling something, 
you should be able to blend in a map which shows the positions of the images of 
the slide show, the current one highlighted, possibly with a route drawn between 
them, the part of the route that is on the same day as the current image in some 
way marked, ...

* for geotagging (manually or by importing a gps track) there is already a kipi 
plugin that uses google map

Actually, I have a local version of a patch implementing the first feature using 
Marble, that has some caveats, though: it currently doesn't work very well due 
to what I *think* are bugs in Marble's handling of changes in the placemark 
model (but I'm not a great C++ programmer, usually doing (and liking!) Java a 
lot more). It uses an intermediate step of generating a kml string - there 
should be a better way. It is a rather large change - I had a lot more than I 
would have liked. It is againt trunk, not against the development branch. And 
(finally) I can't access it for the next week or so, as my main computer has 
broken down recently :-(

I'll try to port it to the development branch and post it to bugzilla soon, but 
I will have only limited time to work on it in the nearer future

The way of implementing maps

The geotagging kipi plugin uses GoogleMap. It does so by using a widget that is 
more or less a web browser. This does work (and you get GoogleMap!), but it 
seems to be a bit "shaky": for some time it just crashed the calling application 
without comment, because google had changed something in the delivered html in a 
way the browser code obviously didn't understand. And it isn't very efficient - 
it works just like GoogleMap in a browser

The KDE way is Marble. Marble can use different sources for the geographic data 
to display, including OpenStreetMap (and so also OpenCycleMap, ...). It does 
*not* support GoogleMap, as far as I know - probably due to licence restrictions.

For overview maps the "standard" data in marble is good. For detailed maps of a 
limited area, OpenStreetMap is usually the best source in marble. Quality and 
level of detail varies however: often good, sometimes excellent (considerably 
better than GoogleMap), but in stranger parts of the world you sometimes don't 
see very much. You can try yourself: http://www.openstreetmap.org/

Integration of Marble is fairly easy. There is (among other possibilities) a 
QWidget ready to use. There are also some bugs, I think, and only limited 
documentation. Much active development.

I would choose marble: it is already usable, much more flexible and I think it 
will grow over time. (though you have to keep up with API changes sometimes...)


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