Re: [Gpsbabel-misc] Position filter has no effect
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robertl
From: Immersive T. <imm...@co...> - 2004-07-06 20:13:20
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This is really getting confusing because on WinXP I'm using the same command and getting zero filtering... gpsbabel -i gpl -f evergreen.gpl -x position,distance=100f -o nmea -F evergreen_filtered.txt This command produces 3674 records (previously I erroneously counted the last blank line) which is identical to an unfiltered version. Then there is Ron's last response which is correct... the last valid point is where you want to compare from, not the last record which may have fallen within the filter distance. ----- Original Message ----- From: "Alex Mottram" <al...@co...> To: "Ron Parker" <ro...@pa...>; "Immersive Technologies" <imm...@co...>; <gps...@li...> Sent: Tuesday, July 06, 2004 1:59 PM Subject: Re: [Gpsbabel-misc] Position filter has no effect > > >None of this is impossible. Bear with us and we'll come up with something. > >FWIW, Alex, I think I'd start with the position filter rather than the > >simplify > >filter. Simplify is based strongly on checking cross-track error, and I don't > >think the two cases are all that strongly correlated. > > > It works. I'm just not certain it makes much sense. evergreen.gpl is a 27 > mile or > so long track. > > the original file: > [alex@machine gpsbabel]$ ./gpsbabel -i gpl -f ~alex/evergreen.gpl -o nmea > -F -|wc > 3674 3674 246158 > > strip the duplicate (stand-still) track points: > [alex@machine gpsbabel]$ ./gpsbabel -i gpl -f ~alex/evergreen.gpl -x > position,distance=0f -o nmea -F -|wc > 3585 3585 240195 > > now ten feet: > [alex@machine gpsbabel]$ ./gpsbabel -i gpl -f ~alex/evergreen.gpl -x > position,distance=10f -o nmea -F -|wc > 3342 3342 223914 > > now strip out all the points that are within 1/2 mile or so of each other: > [alex@machine gpsbabel]$ ./gpsbabel -i gpl -f ~alex/evergreen.gpl -x > position,distance=2640f -o nmea -F -|wc > 1 1 67 > > I guess maybe I just don't comprehend what this will accomplish. I *could* > just have waypoints on the brain > today or something.. > > ? > alex > > > |