Select Setup > Altimeter.

Auto Calibration

Automatically calibrates the altimeter each time the device is turned on. The device continues to automatically calibrate the altimeter as long as the device has GPS signals acquired.

Barometer Mode

Variable Elevation allows the barometer to measure changes in elevation while you are moving. Fixed Elevation assumes the device is stationary at a fixed elevation, so the barometric pressure should only change due to weather.

Pressure Trending

Sets how the device records pressure data. Save Always can be useful when you are watching for pressure fronts.

Plot Type

Records elevation changes over a period of time or distance, records barometric pressure over a period of time, or records ambient pressure changes over a period of time.

Calibrate Altimeter

Allows you to calibrate the barometric altimeter if you know the correct elevation or the correct barometric pressure. See Calibrating the Barometric Altimeter.