Automatic reduction of GPS "jaggies"

[adamschneider]

New feature in GPS Visualizer: "trackpoint distance threshold."

See: http://www.gpsvisualizer.com/tutorials/ ... lters.html

[kepPNW]

Neat algorithm, nicely explained!

[adamschneider]

I actually started thinking about it when we were discussing jaggies in those discussions of the MSH climbing routes. I thought about how I'm loath to let go of my every-5-seconds recording, but I can't help admiring the smoothness of the tracks that I get when I accidentally put my GPS's recorder into "distance" mode. The new filtering option is the best of both worlds: record thousands of points, then boil them down later (while preserving their timestamps!).

I still think manually tracing a track (especially when you have a whole spaghetti-like pile of existing GPS tracks to work from) will give the best results, but this is a whole lot easier.

[kepPNW]

I don't recall whether GPS Track Editor came up in our conversations. I've also found the filters in that to be very useful. It'll do a really quick "Local Inconsistencies" filter run through a track, or let you filter by distance/speed/acceleration, and then accept or reject the filtered points individually. (Actually easier than it sounds. I just pan through and reject ones that are obvious switchback type points.)

http://www.gpstrackeditor.com/

[adamschneider]

Yes, that looks like a really useful application... which does me no good as a Mac user.

[kepPNW]

does me no good as a Mac user.

Oh... Ummm... Nevermind...

[adamschneider]

Necessity is the mother of invention. If there had been good (and free) universal GPS mapping software for the Mac back in 2002, GPS Visualizer might never have been created at all.

[Eric Peterson]

Again, I think it depends on the GPS unit itself, could be wrong since I'm not a GPS expert, heh.

What is a good way to check to see if ones unit is indeed recording jiggity's?

I don't have a option on the newer 62 to put the unit into 'distance' mode.

I only have things like 'record most often' to 'record less often'.

Yes, the 62 has these options, duh on moi!

So I'm guessing if you record by time and set it to the lowest possible setting - that is what's
giving you track jiggity's?

[adamschneider]

So I'm guessing if you record by time and set it to the lowest possible setting - that is what's giving you track jiggity's?

Correct, although you don't have to be on the lowest time setting to capture GPS wandering. Even recording a point once per minute can do it, if you sit still long enough.

Like I said, I want as much raw data as possible. Especially since the lowest distance setting on my GPS is 0.01 miles (53 feet, or 16 meters), and I think that's way too long.