Elevation ?

[+F1rst_Timer]

Sorry this is another newbie question. OK, It is a given that GPSr's have an elevation setting for each waypoint, but is it really beneficial to enter elevations from memory map, for example. Does it increase the accuracy in any way, or is it a complete waste of time ? Does anybody use this feature ?

[+currykev]

Can be handy sometimes...

 

Guess

Edited June 6, 2006 by currykev

[+Simply Paul]

99% of the time it's of no use whatsoever, so unless you want to ensure people climb to the roof of a skyscraper (The Housefamily were telling me about one like this in Toronto which sounded cool) I'd not bother with it.

[+Moote]

Elevation data on a GPS works better if the GPS has a calibrated Altimeter built in. It can be very useful especially in thick fog on a mountain.

[+Mr'D]

or is it a complete waste of time ? Does anybody use this feature ?

Yes and probably not...

unless you cache on foggy mountains

 

[+Moote]

or is it a complete waste of time ? Does anybody use this feature ?

Yes and probably not...

unless you cache on foggy mountains

 

Any mountain can turn bad at any time, even on a day like today (Yes Manchester is sunny )

[+housefamily]

99% of the time it's of no use whatsoever, so unless you want to ensure people climb to the roof of a skyscraper (The Housefamily were telling me about one like this in Toronto which sounded cool) I'd not bother with it.

 

Did someone say my name?

 

It was View Carre in New Orleans - but an excellent cache nonetheless. In the plant room at the top of the tallest building in the area! Very cool ... but even that cache didn't record the elevation.

[+Simply Paul]

My mistakes. *Still* looks like a fun cache though

Moote makes a good point, but how many cachers have GPSrs with built-in atmospheric altimeters? I know my 'umble etrex doesn't like heights much - it recorded minus 198ft while I was several miles above northern Spain.

[+Cryptik Souls Crew]

Moote makes a good point, but how many cachers have GPSrs with built-in atmospheric altimeters? I know my 'umble etrex doesn't like heights much - it recorded minus 198ft while I was several miles above northern Spain.

 

I thought the etrex had atmospheric altimeter in at least one of its incarnations? A pressurised cabin would wreak havoc with it, maybe why your GPS thought it was under the sea?

[Dave from Glanton]

I know my 'umble etrex doesn't like heights much - it recorded minus 198ft while I was several miles above northern Spain.

My yellow Etrex seems suprisingly good with heights - when I get to the top of a big hill I sometimes check what the Etrex says versus what it says on the OS map, and generally it's pretty close. IIRC it got the summit height for Windy Gyle as only about 10 feet higher than the OS map said.

[+John Stead]

eTrex Summit and Vista have barometric altimeters - but like any such they only record accurately if calibrated, though they do use the satellite information to calibrate if altitude or pressure information is not available.

[+Jango & Boba Fett]

My mistakes. *Still* looks like a fun cache though

Moote makes a good point, but how many cachers have GPSrs with built-in atmospheric altimeters? I know my 'umble etrex doesn't like heights much - it recorded minus 198ft while I was several miles above northern Spain.

My humble £55 Magelan Explorist 100 has a built in Altimeter and dosen't like heights below MSL (lots of the Fens and Broads marshes. On the is it useful well theoretically it is as your GPSr has to calculate a 3D postion and the closer the seed point is to your actual position the faster it will lock on from a cold start. However unlike geodetic GPSr's which calculate HEIGHT above WGS84 spheroid all the hobby GPSr's I have seen give an ELEVATION above mean sea level - to spot the difference add 60m to your elevation as calculated from an OS map and if this is the figure your GPSr shows then your getting spheroidal HEIGHT.

 

I suspect that hobby GPSr's hold the Spheroidal Height value to speed up the process and so are only calculating a 2D position and hence less precise than the trilateration 3D solution of a geodetic GPSr.

[+Simply Paul]

Mine's an ancient yellow without an atmospheric altimeter, and it's always been very woolly on heights. Give it long enough with no trees around and it'll settle close (within 100ft) of the OS-given height. But show it a tree or two on a hillside and it'll tell you you're below sea level as soon as look at you. Which makes me glad height isn't much of a factor for most caches.

[Mittellegi]

or is it a complete waste of time ? Does anybody use this feature ?

Yes and probably not...

unless you cache on foggy mountains

 

Any mountain can turn bad at any time, even on a day like today (Yes Manchester is sunny )

 

Can't remember the last time I spotted a mountain in Manchester, foggy or otherwise...

[Mittellegi]

...although I seem to recall a thread about a molehill, or some such other sort of underground system

[nobby.nobbs]

Jango & Boba Fett you live in norwich... do you have any idea what a hill is let alone need an altimeter

[+Jango & Boba Fett]

Jango & Boba Fett you live in norwich... do you have any idea what a hill is let alone need an altimeter

Cos I do, tha's whin you feel on the huh. Like in the phrase "don't eat the pies at Portland Road, cos they'll make make you 'ill".

[+Pharisee]

eTrex Summit and Vista have barometric altimeters - but like any such they only record accurately if calibrated, though they do use the satellite information to calibrate if altitude or pressure information is not available.

 

My GPSmap 60CSx has a built in altimeter too, but to calibrate it you need to be at a known elevation (not too difficult) and you also need to know the air pressure at the time which unless you have a barometer on your Swiss Army Knife, is a bit more tricky.

 

Incidentally, while it usually indicates a 'sensible' elevation, for a short time last weekend, I was walking along a footpath at something over 75,000 ft !!!

[+Jango & Boba Fett]

... do you have any idea what a hill is let alone need an altimeter

Just to prove you wrong here's a fine example of the extensive relief we have in East Anglia.

 

The cache is here and a fine example of big sky Norfolk I must say.

[+John Stead]

 

My GPSmap 60CSx has a built in altimeter too, but to calibrate it you need to be at a known elevation (not too difficult) and you also need to know the air pressure at the time which unless you have a barometer on your Swiss Army Knife, is a bit more tricky.

 

 

I think that elevation and air pressure are alternatives and you don't need both to calibrate. Certainly on my 60CS if I enter a height it immediately tells me that calibration is complete without dropping into the page to input pressure.

 

Now as for walking at 75000 ft - was it a case of head in the clouds?

[+Pharisee]

I think that elevation and air pressure are alternatives and you don't need both to calibrate. Certainly on my 60CS if I enter a height it immediately tells me that calibration is complete without dropping into the page to input pressure.

 

Thanks, John. I did wonder about that and will try it next time I'm at a trig point. I've only just got it and haven't really 'played' with it yet

[nobby.nobbs]

[

 

The cache is here and a fine example of big sky Norfolk I must say.

 

nice and ftf...and must be atleast what? 5 ft above sea level LOL

[+Simply Paul]

Bit more global warming and that cache could end up on an island

[ ] / [ ] Delete as applicable.

[+BareClawz]

One thing thats always puzzled me and that is as I was driving across Norfolk one day a lorry and mini bus came the other way both with Mountain Rescue pasted all over them.

Several options come to mind. Either a mountain had got lost and they were rescuing it. Basic training for mountain rescuers with vertigo. Basic training for mountain rescuers starting on the easy slopes. Or they were lost.

 

BareClawz