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[Closed] Using Garmin GPS to measure distance covered ....accurate on hilly routes?

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[#1197141]

I'm a GPS newbie and just started to use my etrex H . Can anyone confirm whether GPS's are able to take into consideration altitude changes when calculating distance covered ?
e.g if ponts A and B were 1km apart as the crow flies but in between was a mountain would it take into consideration the extra distance required to go up and down (if you know what I mean).
thanks
Bill


 
Posted : 07/01/2010 7:34 pm
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I suppose the way to find out would be to find a tall building , get in the lift then start a tracklog whilst heading to the top floor. If the lift travelled 100 metres would it show 100m or 0?


 
Posted : 07/01/2010 7:39 pm
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If you run the route back with say Tracklogs, the mapping software will make an approximation. If your GPS has got a built in altimeter you can choose to use that data instead of the map data.


 
Posted : 07/01/2010 7:40 pm
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dont think the lift thing will work

I assume it works by knowing your location comparing it to a known Topo and then working out distance due to location.

It would not be able to do speed accuarately either if it was not taking this into account as a very steep hill covers limited linear distance


 
Posted : 07/01/2010 7:45 pm
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In answer to your question...yes.
But different GPS's have different accuracy, built in pressure alimeters etc.

Using mine against a bike speedo and the difference is marginal!


 
Posted : 07/01/2010 7:50 pm
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this has been covered before. In short, it doesn't take into account the extra distance but it makes naff all difference. Even if the entire distance was up a 1 in 3 hill, it would be out by 5%.


 
Posted : 07/01/2010 7:51 pm
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hmmm not so sure Horatio ..but I'm not a mathmetician.


 
Posted : 07/01/2010 8:16 pm
 br
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Not sure about not making a difference; as I've a ForeTrek Garmin and on Sunday in the North Downs I measured 19.0miles on it while a buddy measured it at 19.9miles on his bike computer. In more hilly terrain the difference is usually more than 10%.


 
Posted : 07/01/2010 8:24 pm
 Del
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gps works essentially by traingulation, but with more points ( if that makes any sense! ). up,down or around and about, all dimensions are treated equally as far as i am aware. may not be mega acurate but should be pretty good assuming decent sattelite coverage.


 
Posted : 07/01/2010 9:14 pm