Garmin edge elevation data?

[gaz]

Using an edge 705. i've just noticed today a HUGE irregularity with the elevation data.

At work today my said elevation was -35 feet. and when i got home it was 220ft.
On my tuesday commute, work elevation = 307ft and when i got home it was 270ft.

My total gain and loss seam to be consistent but the starting and ending points don't :S

 

[simon walsh]

Have u downloaded all available update form the connect website?. I had similar problems and this sorted it.

 

[fossyant]

Mine did -35 in the house, but lack of GPS locks etc and silly temps....

Fine outside so far.

 

[gaz]

will the temp effect it that much?

 

[fossyant]

New user myself - had it switched on inside the home with no GPS lock, whilst freezing outside (high pressure) - did you have a good lock before setting off ?

 

[gaz]

I waited to get a single outside. so as good as it could be.

 

[Dave5N]

Basically it's bollocks. According to the 705 My house goes up and down more than a proverbial *****'e proverbial ******s.

It's ok for fun, but many a loop ride seems to finish 20' or 30' lower than it started.

Perhaps the Earth is shrinking? Global warming causing it to evaporate?

 

[gaz]

did some digging and it's because it uses a Barometric altimeter, the air pressure is changing with different weather etc.. and that why my gain and loss is always similar.

 

[Auntie Helen]

Yep, I've got an Oregon 300 with barometric pressure and I'm currently sitting at my desk 400metres below sea level (and I'm right by the coast!)

 

[gavintc]

Yes, the 705 is not reliable as a height measuring instrument. I have noted when crossing alpine passes that relying on the indicated height can lead to significant disappointment when you find that you still have 100 m more climbing to go. It might not seem a lot, but when you have worked hard for an hour, counting down the meters, it pisses you off somewhat.

Equally, I have compared height gained in a cafe stop with other 705 users and our heights gained have been different despite being in the same group all day.

 

[piedwagtail91]

don't know about the edge 705 but i calibrate my vista hcx before every ride ,though it's never that far out!