The Edge Touring Plus, 1000, 810, 800 and 510 calculate elevation data using a barometric altimeter. Once the device is properly calibrated, the standard area of accuracy will be +/- 10 feet. To ensure that elevation data is accurate at the beginning of an activity, calibrate the elevation manually.
To calibrate the elevation manually:
The elevation will then be calibrated from this manually set elevation.
The barometric altimeter is not temperature compensated. Temperature changes in the measuring device will affect the barometric pressure sensor and altimeter readings.
*If Location memory is full, marked locations can be backed up using BaseCamp.
Garmin BaseCamp: http://www.garmin.com/en-US/shop/downloads/basecamp