Nikon 1 aw1 Reference Manual page 127

A
Heading
Except when the camera is oriented with the lens pointing directly
upward, the heading provided by the built-in electronic compass is
recorded with all pictures taken with 1 NIKKOR AW 11–27.5mm f/3.5–5.6
and 1 NIKKOR AW 10mm f/2.8 lenses. Headings are approximations only
and are not intended for navigation: accuracy drops with other lenses
and may be affected by the presence of magnets, metal objects, elec-
tronic equipment, and power lines. The camera may also be unable to
provide accurate headings underground or inside a vehicle or building.
The compass can be calibrated as described on page 114.
A
The Virtual Horizon
The camera uses a built-in accelerometer to show the amount the cam-
era is tilted left or right (roll), in increments of 5°. The reference line
turns green when the camera is level.
Camera tilted left
The accuracy of the display drops when the camera is angled sharply
forward or back. If the angle is so sharp that the camera is unable to
measure tilt, tilt increments will not be displayed.
Camera level Camera tilted right
O
102