I tried to search a bit but couldn't find much info about the libgarmin project. But from what I found, it appears to be a parser for Garmin map files, so a vector map renderer would be needed to actually draw the map from the parsed data.

ModRana currently has no vector map renderer and all map layers are created from tiled images. So, it doesnt look too good for libgarmin in the short term...

In the long term, I plan to find some renderer that integrates well with Python and Py/GTK to add vector map support to modRana. Then I can try to somehow wrestle it to also render Garmin maps