Re: [Gpsbabel-misc] GPSBabel Filtering

[Ron P. <ro...@pa...>]

Richard Mikalsen wrote:
> Hello!
>
> Is it possible to change the way the filter works when filtering 
> duplicate waypoints?
>
> As far as I know, the output only contains a list _without_ 
> duplicates, but I would like to have a list of _only_ the duplicates.
>
> I'm using GPSBabel v1.3.3

That's not one of the options that's built in to the filter, but you can 
get those results with a little work:

gpsbabel -i gpx -f in.gpx \
  -x stack,push,copy \
  -x duplicate,location \
  -x stack,swap \
  -x duplicate,location,all \
  -x stack,pop,append \
  -x duplicate,location,all \
  -o gpx -F out.gpx

This reads your file, makes a copy of it, removes all but one of any 
duplicated waypoints, swaps the one-of-each-waypoint copy with the copy 
of the original, removes all duplicate waypoints from that, and then 
sticks both copies of the list together again.  This leaves exactly one 
of any waypoints that were originally duplicated, and two of any that 
were not.  Then it uses the duplicate filter again, removing all of the 
waypoints that were originally unduplicated.

It isn't pretty, though, nor as fast as it could be.  If you're doing 
this a lot, and if you know some C, you might consider adding an option 
similar to the arc or polygon filters' "exclude" option to invert the 
sense of the test.