Gpxaltitude is a simple tool which allows to fix altitudes in GPS traces encoded in GPS Exchange Format (GPX).
gpxaltitude [ -v ] [ -a n | -r n ] file\n
- The
-a
(absolute) parameter sets the starting altitude to a known absolute altitude and fixes all the following altitudes accordingly. - The
-r
(relative) parameter applies a positive or negative relative change to the altitudes. - The
-v
parameter increases verbosity on stderr.
When no parameter is given, altitudes are simply rounded to the nearest centimeter.
Decrease the altitudes values by 24 meters:
gpxaltitude -d -24 trace.gpx >trace_fixed.gpx
Set the starting altitude to 1257 meters:
gpxaltitude -a 1257 trace.gpx >trace_fixed.gpx