Elevation

[Older]

How do Garmin and Polar etc. determine elevation?

[stewie911]

Barometric

[AndreZA]

I want to know why after a ride starting and finishing at the same spot that the ascending and descending figures don't match. Surely if you ride downhill 200m you need to climb 200m.

[Tumbleweed]

I want to know why after a ride starting and finishing at the same spot that the ascending and descending figures don't match. Surely if you ride downhill 200m you need to climb 200m.

 

How far out is it usually?

[AndreZA]

How far out is it usually?

 

in the tens of meters.

[Tumbleweed]

in the tens of meters.

 

I found this when I first clicked on this thread:

 

http://gpsinformation.net/main/altitude.htm

[Yang]

Where I ride is as flat as a snooker table, there and back ride of 33,5km as a speed trial. But my Polar indicates altitude gains of from 0 to 50m on different days. I think its got to do with the temperature variance during the ride affecting the barometric pressure, which is how the Polar measures altitude.

[Delgado]

I believe Jacques Kallis is brilliant at determining this!!!

[DirtyFrank]

How far out is it usually?

 

My Polar CS600 always under reads by 10-15% when compared to GPS units. This is probably due to the recording interval and the relatively slow adjustment cycle of the barometric units. I am sure that GPS units are more accurate.

[Mellow]

I want to know why after a ride starting and finishing at the same spot that the ascending and descending figures don't match. Surely if you ride downhill 200m you need to climb 200m.

 

temperature changes

[scotty]

Kinda like yesterdays indoor stationary ride, according to my Garmin i had 14m ascent and 17m descent.

[1hill@aTime]

Kinda like yesterdays indoor stationary ride, according to my Garmin i had 14m ascent and 17m descent.

 

do you have wooden floors

[scotty]

Nope, tiled floors Hilly1.

 

Could be my house is sinking though, i started on 1624m and finished on 1621m

[1hill@aTime]

Nope, tiled floors Hilly1.

 

Could be my house is sinking though, i started on 1624m and finished on 1621m

 

It's global warming, *grabs tin foil beeny*

[andrewc]

Garmin Connect has an Elevation Corrections option for each training session that you upload. I ride a loop on Manning Road and the elevation at the same points gradually increase (generally) during the training session:

 

 

Enabling Elevation Corrections fixes the elevation data:

 

 

Might be handy information for the Garmin owners out there.

 

Cheers,

 

Andrew

[Tumbleweed]

I believe Jacques Kallis is brilliant at determining this!!!

 

 

That's a classic story…