Google Earth 5.2 (released yesterday) adds some really spiffy stuff for
visualizing terrain profiles and sensor data. Obviously, a very important
source of such data is tracks from GPS units and associated file formats.
I've just checked in the new KML writer that writes all these new tags.
Heart rate, wheel cadence, cyclist power output, and such are now supported
in ExtendedData tags inside the new gx:Track. Also new is a 'segment'
option to the track filter that tries to create track segments when a track
is "obviously" disjointed, as calculated by an atypical jump in distance or
velocity such as would happen when the GPS has been turnred off and moved.
I don't know of any other changes in progress (well, there's the video
change still awaiting test case....) so I plan to make a non-beta GPSBabel
release within the next week or so.