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GPS Altimeter

Community Veteran
Posts: 1,236
Registered: 02-08-2007

GPS Altimeter

I bought a Garmin Etrex for hillwalking not because I need it but just because I like gadgets and I wanted to be able to save all the info to plot on a map.
I knew that GPS altimeters were absolute rubbish so I paid a little more for a model with a barometric altimeter although I have found this to be a problem. I knew it would change over time with the weather and would need calibrated with every use but I am shocked by how much. I turned it on this morning, calibrated it to 115ft as I know that is the altitude of my house. Already it has dropped 50ft without ever moving! Looking at the local weather for today I can see why but I was hoping this would not have such a large effect so quickly.
So my question is, other than topography maps, is there just no way to gauge accurate altitude? If only Google maps had this option based on topo on my Android, that would be ideal at least for calibrating the Garmin at regular intervals during a long days walking.
20 REPLIES
pierre_pierre
Grafter
Posts: 19,757
Registered: 30-07-2007

Re: GPS Altimeter

I have ViewRanger maps on my Mobile, that for the UK has all the spot heights, and it gets your location via GPS, think you can get them for Eire & Northern Island  http://www.viewranger.com/ 
Community Veteran
Posts: 1,236
Registered: 02-08-2007

Re: GPS Altimeter

Great, now I see it. All I had to do was go to Android market instead of spending £150 on a Garmin!
A well, I still like the Garmin though.
Community Veteran
Posts: 1,236
Registered: 02-08-2007

Re: GPS Altimeter

Strange though, they have maps for Great Britain and maps for Republic of Ireland. In that case NI has been left out?Huh
OMG, it actually has!! What about the Mournes?
pierre_pierre
Grafter
Posts: 19,757
Registered: 30-07-2007

Re: GPS Altimeter

their contacts in Cambridge are very good, answer e-mails the same day, and the boss answers the phone, they also have a lousy scale for mainland Europe by the look of it
Community Veteran
Posts: 1,236
Registered: 02-08-2007

Re: GPS Altimeter

I really don't understand how they have missed us. Could they not had maps for UK instead of just Great Britain or maps for All Ireland instead of just the Republic?
Looks like my Garmin will have to do. I do have an old fashioned (waterproof) folded map of the Mournes, very detailed, and the Mourne Wall being like a handraill in the cloud, I am not likely to get lost.  Smiley
pierre_pierre
Grafter
Posts: 19,757
Registered: 30-07-2007

Re: GPS Altimeter

It probably dates back to the "Troubles" the best I have are the 1/250000 of all Ireland, and in a box in the loft some larger scale from Rally days about 20 years ago, have got some GB on my phone at 1/25000 and all Britain/Wales at 1/50000, the pink areas are the large scale ones, get some more when I have save up, but it is a lot cheaper than the paper ones
Community Veteran
Posts: 6,735
Thanks: 12
Registered: 02-02-2008

Re: GPS Altimeter

OSNI have very detailed digital maps; I suspect it's down to how much they charge for them...... Roll eyes
itsme
Grafter
Posts: 5,924
Thanks: 1
Registered: 07-04-2007

Re: GPS Altimeter

Quote from: Sean
I knew that GPS altimeters were absolute rubbish

If they are rubbish will they also give wrong positional information? We live on a 3D planet.  Smiley
pierre_pierre
Grafter
Posts: 19,757
Registered: 30-07-2007

Re: GPS Altimeter

they currently give a ground accuracy of about 10 M, but vertically the triangulation from three satellites is not that accurate, better if 6 are in view,  I saw a report this week that the top of Japan has moved about 5 metres and the maps have got to be redrawn
pierre_pierre
Grafter
Posts: 19,757
Registered: 30-07-2007

Re: GPS Altimeter

Just found one of my old maps, it is a one inch map of the Armagh area dated 1962 sheet no 8 and cost six shillings
pierre_pierre
Grafter
Posts: 19,757
Registered: 30-07-2007

Re: GPS Altimeter

pierre_pierre
Grafter
Posts: 19,757
Registered: 30-07-2007

Re: GPS Altimeter

some of the ins and out of how they locate you is here for domestic http://www.gpsworld.com/consumer-oem/handheld/down-and-deep-10830
lots more on that site about professional use
pierre_pierre
Grafter
Posts: 19,757
Registered: 30-07-2007

Re: GPS Altimeter

Sean, just had another look at the Viewranger set, the Ulster set  does cover the Mourne Mountains, but it is a lousy scale
IE Regions: Ulster (Eire) Download
ViewRanger software with OSi 1:50,000 topographic mapping for Ulster province (Eire counties only). Covers Cavan · Donegal · Monaghan .
IE Regions Ulster (Eire) Map Data: 114 MB
Price: £40.85 / €49.02 (Including VAT at 20%
pierre_pierre
Grafter
Posts: 19,757
Registered: 30-07-2007

Re: GPS Altimeter

you can get all the bites around the border for £20, you dont have to buy the set, I have just selected the bits in red, that is just £20