[Geowanking] GPS Track Software

[Anselm Hook]

Carden's algorithm works well but it is slightly inefficient; you probably
want to only manufacture points once you know the set is reduced to below
200 elements.

His algorithm is effectively:

  loop forever
       visit all points
           discard points that don't contribute enough to the polygon
       break if total set of points is < 200
       else decrease resolution to get a coarser approximation

And you want the same algorithm but to not actually make google map points
unnecessarily...  so only do that once after you find the polygon or some
such thing.  Also calling parse float over and over may be costly...  and
maybe you can do a binary split or go from the other direction...
requires testing.  It still is pretty slick though - we use this in
thingster in http://thingster.org/p2pmap/googlemaps/inner.html ...  I have
not improved it yet.

Another improvement would be to take the datestamp of any associated
photos and automatically place them along the line segment...  also pretty
trivial...  If you export correctly from your digital camera then the
datestamp on the file is ok, otherwise you have to peek inside the jpeg.

 - a


On Mon, 15 Aug 2005, Tom Longson wrote:

> Go check out GPSBabel. It's free, and works on Windows, Mac, and
> Linux. Rich Gibson did an excelent writeup on how to use it in
> O'Reilly's "Mapping Hacks" (get it if you're interested in
> cartography, it's pretty cheap too).
>
> To view your tracks, you can use the Google Maps GPX Viewer:
> http://www.tom-carden.co.uk/googlegpx/
>
> Good luck! If you're going to Burning Man, meet up with some of us
> Geowankers at the Brane village (Catharsis and 8:00) on Thurday at
> 4:00pm. We can probably help you out a bit since I know there will be
> people there who are "GPS virgins".
>
> nym
>
> On 8/15/05, Kyle Mulka <kmulka at glc.org> wrote:
> >
> >
> > Couple of questions for you guys and gals:
> >
> > Where can I get a list of GPS software along with general features?
> >
> > Specifically I'm looking for a piece of software (preferable free) that will
> > import from my Garmin eTrex and export to GPX or similar easy to parse
> > format.
> >
> > I've already looked at GPS TrackMaker (which doesn't have GPX) and EasyGPS
> > which doesn't import tracks for some reason (probably because they want you
> > to buy the pro version).
> >
> > Also, what are some of the most popular tools for downloading GPS data to
> > your computer? (doesn't have to be free)
> >
> > -Kyle Mulka
> > http://maps.kylemulka.com
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> >
> >
> >
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