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Track Log Errors in Canyons -- Rim to Rim

Started by Seldom, September 27, 2011, 01:26:49 PM

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Seldom

I just took my 62s to the Grand Canyon and walked down the North Kaibab trail to Phantom Ranch and up Bright Angel the next day. (Not 1 day RimtoRim like the fanatics do it.)

Track recording method was set to Auto and recording interval was set to Normal. 

The hike from North Rim to Phantom is listed as 13.3, but the 62s showed 17.3.
The hike from Phantom up Bright Angel is listed as 10, but the 62s shows 11.

The added mileage can be seen on  the track as series of spurious track points, some hundreds of feet off.

Anybody here found settings to minimize these errors?

Yenalom

Look at:

        http://www.trackprofiler.com/

The application is in development. It does allow you to load a GPX file and make corrections (semiautomatically, I believe).

Otherwise, I guess you have to edit the track manually.

Bob M



Seldom

Thanks for the link, but I've got lots of ways to edit tracks.  I'm looking for ways to get my 62s to record it reliably in difficult conditions.  Canyons are a particular problem for me.

jbensman

Make sure the GPS has a good lock is the best you can do. 

I always set the track to auto, most often.  That tends to get the best track.  But that cannot help with bad points.  You can erase bad points in mapsource with the eraser tool. 

rban

I don't have any tricks either.  However, if it is any consolation, we hiked rim-to-rim on the same trails you did in early September.  My Garmin 310XT recorded 17 miles from the North Kaibab trailhead to Phantom Ranch.   This is the same as  what yours did.  I recorded 10.74 miles from Phantom Ranch to the trailhead of the Bright Angel Trail.

It seemed like we were never going to get to Phantom Ranch since the trail just kept going and going.  Since the distance was off so much, I thought it was just around the next bend over and over.  I wish  I had manually entered the lat/long of Phantom Ranch before the hike so I could have a "GOTO" at least tell me the straight line distance.

Seldom

I'm consoled. 

I find downhill harder than uphill so it also seemed to me like the hike from Roaring Springs to Phantom would never end, and I was using a routable trail map (Desert Southwest) and monitoring my distance to destination field. 

Of course, with spurious location data, the distance to destination could be demoralizing.  From time to time it would jump from x.75 miles to x+1.25 miles.  Don't know which of those distances were in error.  Probably both.

Most of my spurious track points were north of Roaring Springs, but there were enough in the Inner Canyon to psych me out.

Stew and lemonade sure tasted good when I got there though.

puzz

Quote from: Seldom on September 28, 2011, 05:59:10 PM
Thanks for the link, but I've got lots of ways to edit tracks.  I'm looking for ways to get my 62s to record it reliably in difficult conditions.  Canyons are a particular problem for me.

As far as I know, there is no way to solve your problem. In canyons satelite visibility is bad and, even if the visibility *is* good, the reflections from the stones around you "confuse" the GPS device. And errors happen.

That's why I decided to make my own app for the removal of GPS or elevation errors.

If you find a GPS that don't have this problem -- please let me know.

PS. Disclaimer: I'm the author of the beforementioned trackprofiler app. Thanks for mentioning it Yenalom!