[sanjuro]

Or do have to have an altimeter (which I believe handheld ones work on air pressure)?

 

[binary visions]

Many (most?) do.

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

almost any calibrated altimeter will be more stable at reading altitude than a GPS.

I handled one that had an altimeter on it but didn't get a chance to really experiment with it so I don't have much more information than that.

 

[sanjuro]

this is what confuses me:

You might like the eTrex Vista Cx because it has these features:

* Electronic compass and barometric altimeter

 

[binary visions]

this is what confuses me:

You might like the eTrex Vista Cx because it has these features:

* Electronic compass and barometric altimeter

Yeah, the barometric altimiter is becoming more popular because it doesn't require a clear line of site to the sky to give you an accurate reading. Most other GPS altimiters work on satellite readings.

 

[Westy]

GPS data isn't very accurate for altitude, at leas compared to the 2d position data. From when I was shopping for GPS's the only ones that would provide elevation data in any kind of chart had a barometric altimeter. I have a Suunto watch with a built in altimeter, great for tracking climbs on rides. For road rides I kind of use it as a poors mans power meter and use it to pace myself on long climbs.