GPS tracks in GPX format can be added to a map as overlays. The format to be used is [map context="node/{nid}/context" layers="a,b" a="gpx|path/to/first/gpx|1st Title" b="gpx|path/to/second/gpx|2nd Title"/].

Note that when multiple gpx tracks are shown, only the last one will show popups when selecting the waypoints.