garmin etrex

[guest]

Which one of these is optimal for examining your track? I had heard the summit but someone else I talked to today seemed to think the vista would be better. Anyone else?

[guest]

Hello there!
eTrex Vista has got exactly the same functions as eTrex Summit (GPS+pressure operated altimeter+digital compass) plus it has got mapping capabilities. In my opinion, eTrex Vista is the Rolls Royce of portable GPS's!!! You can download maps onto your eTrex Vista!!!
Downloading Oziexplorer software and with the right functions of it, you can plot the profile (forward movement/altitude) of your track!!! It works very well!!! But if you want to exactly quantify your tracking efficiency, you must download "by hand" (if anybody knows an automatic method, please tell it!) the figures for forward movement/altitude points and then write them down (again by hand) on an Excel worksheet and then have Excel to calculate the exact numbers. But, after all this hard work, you know exactly what your track was!!!
Stay safe out there
Blue Skies
Andrea
#689

[crwper]

I've written some software that downloads and displays the actual points in three dimensions from a Garmin GPS. It would be pretty easy to quantify things from there, or to dump the points out to a text file which is easily read into Excel. The only hitch is, the code is attached to a rather elaborate bit of seismic survey design software. :'(

If anyone knows an existing bit of free software that can do these things, let me know. Otherwise, I guess I could spend a few hours putting something together. Let me know what kind of functions you'd like to see.

Or, if I've completely misread the problem here, let me know that too.

Michael

[Craig]

This site had a pretty good tool for visualising GPS data. Check out the Shockwave viewer (requires Shockwave - duh!) at:

http://www.gpsdrawing.com/gallery/poxon.htm

Also, have a look at the Draw menu where you can plug in your own data into the tool.

I've only used the wingsuit from a plane. I tried to get Yuri to send in some of his data, since he's the one who started publicising the use of logging GPS, but he hasn't got round to it so far. The hike up Kjerag might be quite interesting too?

[guest]

Michael, Craig,
you both understood perfectly well. Next weekend I am going to give a try to Craig's software.
In simple words, to be able to quantify the efficiency (of your track, of your track with wingsuit, of your flight under canopy, etc.), all you need is a "straight line" of your flight path and the altitude of relevant points, in order to be able to do a "finite derivative" (simpler to do than to explain), that is the ratio between the distance travelled forward and the distance fallen vertically (between two succeive points of flight). This is your flight efficiency, any which way your flight is made.
Any piece of software capable of downloading data from Garmin GPS, collect these data into a file, better if into an Excel file, and with the triple set of data for each point of flight (lat, long, altitude), get the "stretched" (or rectified) horizontal line of your flight and so at the end, getting out of the previous old "triple" set of data a new "double" set of data, made by the couple "horizontal distance/altitude". From there, if in an Excel file, it is very easy to have Excel to calculate "efficiency".
OziExplorer is a fantastic piece of software, which also gives you a very nice plot of your "stretched" horizontal flight line and corresponding altitude (and if with the pointer of your mouse you go over a point, for few seconds you are able to read "horizontal" distance and altitude): copied by hand and re-written onto an Excel file, I proceed with the calculation of "efficiency", very precise but at the same time very time consuming. I wish to have something more automatic.
In my latest GPS tracked freefall (with just my body), while tracking with the penguin technique, I got a maximum penguin track efficiency of 0.37, but: 1) I am not such an incredibly good tracker; 2) it was only the second time I was doing the penguin track.
I shall let you know more once I get more flights with my eTrex Vista and more data.
Stay safe out there :D
Blue Skies
Andrea :7
#689

[guest]

Can you use the summit though? I don't wanna spend $350 on the vista if all i get extra are maps. I just wanna plot my track after every jump. it does store that right?

[guest]

1st: on http://www.gpscity.com , asking them a quotation, you should be able to get a quotation for eTrex Vista around 300$
2nd: yes, you can use perfectly well an eTrex Summit for logging your track, download data, etc. etc.. The only difference between eTrex Vista and eTrex Summit is that eTrex Vista has got mapping capability (included download of maps from MapSource) and eTrex Summit has not: all the other functions are exactly the same.
Stay safe out there :D
Blue Skies
Andrea :7
#689