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DAKOTA4X4

?? About Tracks + Legs on Garmin Etrex ?

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Is there a website that explains these terms and how the GPS uses them,EG my etrex says it saves so many legs per track.I know this ? is redundant to most of you but the manual that comes with the etrex does not explain this very well to someone that has never used a GPS.Thanks to all who can offer advice on this and direct me to a site with some good definitions on these terms.Yours truely DAKOTA4X4. icon_biggrin.gif

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First, there are two distinct types of tracks. There's the "active" track, sometimes called the breadcumb trail, that is basically a long list of the last 1500 (roughly) unique positions it's recorded, and usually good for several hour back. Easch reading contains Lat&long, the altitude, and the time. When you download this into something like EasyGPS, or Mapsource, then you get all that information.

 

However, from inside the GPS, you can save a portion of the active log, and make a saved track, and that's what your manual talks about. Becuase it would take too much memory to save the original track, garmin has come up with an algorithm to reduce the number of points needed to represent the track. In the case of the basic etrex, they pare it down to about 20 points. A "leg" is the span between two points, and if there are N points, then there are N-1 legs (it's the fencepost problem).

 

When you save a track, you lose not only a lot of detail, but also all time/date and altitude information, therefore for serious analysis, I prefer to leave it in the active log, and download that directly using ExpertGPS, Mapsource, or G7toWin. (G7toWin allows you to export to a comma separated list, which imports nicely into a spreadsheet, so you can do funky things to it.

 

-- Mitch

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Thanks a bunch there Pneumatic = Mitch,i have never had it explained that well its to bad the people that make the manuals dont explain it like you did so the average person would understand.Thanks again for takeing the time to help someone new to the gps game.Yours truely DAKOTA4X4. icon_cool.gif

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