direction indicator; heading indicator; compass (non-magnetic)
Refers to an instrument that shows direction or heading, often a non-magnetic compass used in aviation, navigation, or surveying. The term emphasizes the device rather than the magnetic needle.
The airplane's cockpit is equipped with a heading indicator.
This direction indicator shows direction without using magnetism.
方位磁石 specifically means a magnetic compass. 方位計 can include non-magnetic instruments like gyrocompasses or GPS-based indicators.
Compound of 方位 (direction, bearing) and 計 (meter, gauge). The term is a straightforward technical coinage for a direction-indicating instrument.