This format can...
read and write waypoints
This format has the following options: datum .
National Geographic Topo! Waypoint and Route Format. This module reads and writes .TPG files created by various editions of NG Topo! Reading/writing of route data is not supported yet.
Contributed by Alex Mottram.
The option 'datum="datum name"' can be used to override the default of NAD27 ("N. America 1927 mean") which is correct for the continental U.S.
Any legal datum supported by GPSBabel may be used. For example, points in Hawaii should use "Old Hawaiian_mean".