Directional compass
Distinguish measured heading, facing, sitting and their axis with the Earth plate’s twenty-four mountains and Later Heaven directions.
Measurement convention
This page uses the Earth Plate standard-needle 24 Mountains: north is 0°, angles increase clockwise, and each sector spans 15°. The direction toward the top of the screen is the facing direction; the opposite direction, 180° away, is the sitting direction. Sector and palace assignments follow the standard-needle directions in volume 2 of Qinding Xieji Bianfang Shu.
Coordinates record only the measurement location; they cannot alone determine a building’s orientation. Phone headings may reference magnetic north and be affected by metal, magnetic cases and indoor surroundings. For formal use, avoid interference, calibrate and repeat measurements.