best altitude and track log?

[gonebush]

Hi all,

At the moment I walk electronic technology free (apart from Epirb and sometimes satphone) but I am planning a month long hike in Nepal in April and would like to record a track log and particularly an altitude log. I am picturing somehting that can be downloaded and provide a graphical representation of the walk profile. It was wondering if anyone has a good setup that would do this or if anyone knows whether this can be done with any of the altitude or compass watches? If i can find somethign that works then I am thinkning it owuld be great to start a thread where people can record and load walk profiles from all over the place.

My apologies if these has been covered in a previous post but I have done a few searches and havent found anything.

cheers

[wander]

How long between access to mains power re-charge? Or what will be your longest period without mains power?

[gonebush]

I know in Nepal you can get power almost daily in tea houses but for use back home it could be up to a week on tracks in Tassie or Flinders Ranges. Nepal is also a bit different because once you get up tot he higher al;titudes you are often only walking for half a day (3 - 5 hours) to ensure you get good acclimitisation so i am imagingin i could turn things off and get longer life.

I havent used any of the solar panel setups or external batteries buyt i ahve read information in a couple fo threads here about these options.

[frenchy_84]

Recording heights (to a known datum) in the Himalaya will be interesting.
Firstly make sure you have a GPS that does not record heights by using an altimeter. Lonely Planet Hiking in the Nepal Himalaya states" If you carry a properly calibrated altimeter on a trek you will find that it agrees with elevations listed here up to an elevation of about 3500m. At higher eleviations your altimeter will read lower than the elevations in this book and shown on maps. Altimeters are calibrated to compensate for temperature change according to a standard formula that doesnt fit Nepal's climatic conditions. This causes the altimeter to read 416m low at 4000m and 650 low at 5000m. To be accurate record the temperature and make necessary conversion to obtain the correct altitude. Read your altimeters instruction book for more details." The improtant bit to take out of that is that the error is not linear/consitent so altitude plot would be screwed.

Now, using GPS measurement heights, will provide ellipsoidal heights (ie not relative to sea level). I have no idea what kind of datum is used in the himalaya, or if they have any conversion to sea level (im sure they do somewhere). Also out of anywhere on earth, I imagine that in the himalaya you will find the most extreme differences between ellipsoidal heights and Geoid heights (sea level). However the difference will remain relatively constant so while ellipsoidal heights may not give you true heights atleast your altitude plot will have reasonably good relative accuracy.

So after all this rambling make sure you have a GPS that doesnt use an altimeter to measure elevation.
PS I plan to be walking the 3 passes trek in April, which trek are you doing?

[photohiker]

If you just want to log your walk, then a GPS data logger might be the way to go.

Like this: Holux M241 GPS Logger

Uses AA battery and gets 12 hours per Alkaline. Cost on ebay is sub $100

[gonebush]

HI Frenchy,

thanks for the info. The only info I have found for a datum in Nepal is that most seem to use WGS 84. SO it is probably not the best for navigation but should give a reasonable track for a record. I hadnt thought out about the temperature impact on calibration and maybe getting an accurate altitude log is not going to be possible.

The GPS data logger might be an option but im still not sure if this woudl provide the ability to produce a walk profile. Is there software that you would need to interprate the data file?

By the way I am flying into Phaplu and heading up Gokyo and then across Chola Pass, a side trip to EBC and then across Kongmala Pass for a trip up Island Peak. Well this is the plan anyway, but we will see how we go once we are on the ground.

[photohiker]

The GPS data logger might be an option but im still not sure if this woudl provide the ability to produce a walk profile. Is there software that you would need to interprate the data file?

Yes, you would need software to extract the data from the logger. If you wanted to represent the data as a walk profile, you would need suitable software or web service to do so. It's a pretty generic function and pretty popular too with various exercise fanatics including bushwalkers.

eg: http://www.everytrail.com/view_trip.php?trip_id=1436417

If you click the little icon on the bottom of the map that looks like a lightning bolt you will see the profile.

Cheers

[gonebush]

Thanks for that. The everytrail site looks quite good and is pretty much what I am looking for. Thanks for the heads up.