Add a lossless import/export format

From looking through the source code it seems that csv is the only format which 
exports all data, in particular speed and bearing, and this can't be 
reimported.  As a track is being recorded these figures, which are coming from 
the gps provder, are already averaged.  Thus, the averaged figures are stored 
in the database and used for charts.

When exporting as either kml or gpx, the only importable formats, the speed and 
bearing figures are not exported.  When reimporting, the code simply calculates 
these from the previous data point, so the values are different to the 
originals as the averaging has been lost.  This results in the speed chart 
being quite different to what it should be (it generally seems to contain large 
spikes following a period of no movement).

It would be nice to have a lossless export format which writes all the data 
fields out and can then be reimported as an exact copy of the original.  This 
could also be used on the google drive synchronisation, as I see this currently 
works by exporting the kml format.

The only way I found of transferring tracks to my new phone without any loss 
was the backup/restore feature which obviously dumps the entire tables and 
therefore includes these extra fields.  Although this process works, it can't 
be used for single tracks as it overwrites all data.

Original issue reported on code.google.com by martynsm...@gmail.com on 23 Jan 2014 at 12:42

irfan-arshad-arbisoft / mytracks

Add a lossless import/export format #1439