24-direction chart
Starting at north (0°) and going clockwise, each of the 24 sectors spans 15°, 7.5° either side of its centre.
| Name | Centre | Range | Name | Centre | Range |
|---|---|---|---|---|---|
| Zi 子 | 0° | 352.5–7.5° | Wu 午 | 180° | 172.5–187.5° |
| Gui 癸 | 15° | 7.5–22.5° | Ding 丁 | 195° | 187.5–202.5° |
| Chou 丑 | 30° | 22.5–37.5° | Wei 未 | 210° | 202.5–217.5° |
| Gen 艮 | 45° | 37.5–52.5° | Kun 坤 | 225° | 217.5–232.5° |
| Yin 寅 | 60° | 52.5–67.5° | Shen 申 | 240° | 232.5–247.5° |
| Jia 甲 | 75° | 67.5–82.5° | Geng 庚 | 255° | 247.5–262.5° |
| Mao 卯 | 90° | 82.5–97.5° | You 酉 | 270° | 262.5–277.5° |
| Yi 乙 | 105° | 97.5–112.5° | Xin 辛 | 285° | 277.5–292.5° |
| Chen 辰 | 120° | 112.5–127.5° | Xu 戌 | 300° | 292.5–307.5° |
| Xun 巽 | 135° | 127.5–142.5° | Qian 乾 | 315° | 307.5–322.5° |
| Si 巳 | 150° | 142.5–157.5° | Hai 亥 | 330° | 322.5–337.5° |
| Bing 丙 | 165° | 157.5–172.5° | Ren 壬 | 345° | 337.5–352.5° |
The set combines the 12 earthly branches (Zi, Chou, Yin…), 8 of the 10 heavenly stems (Jia, Yi, Bing, Ding, Geng, Xin, Ren, Gui) and 4 trigrams (Gen, Xun, Kun, Qian).
Sitting and facing
"Sitting A, facing B" means the back is toward A and the front looks toward B. The two are always 180° apart.
| Expression | Back toward | Facing |
|---|---|---|
| Sitting Zi, facing Wu | N (0°) | S (180°) |
| Sitting Ren, facing Bing | NNW (345°) | SSE (165°) |
| Sitting Gui, facing Ding | NNE (15°) | SSW (195°) |
| Sitting Gen, facing Kun | NE (45°) | SW (225°) |
Which north?
A traditional luo pan uses a magnetic needle, so it reads magnetic north. Maps, architectural drawings and site plans use true north. With sectors only 15° wide, a declination of 10° or more (New York about -12.5°, Los Angeles about +11.3°) easily moves a reading into the next sector.
For example, a house facing due south on the plan (180°, Wu) reads about 192° on a compass in New York, which falls in Ding. Agree on the reference before comparing. See magnetic vs true north.
Reading it on a phone
The bearing in the Android app "Compass Camera" is magnetic, the same basis as a luo pan.
Point the way the building faces
Stand facing the same way as the front of the building, hold the phone upright and read the number, then look it up in the chart. 186° falls in Wu (172.5–187.5°), close to the Ding boundary.
Keep a record with Stamp bearing
Turn on "Stamp bearing" and the bearing and time are printed on the photo, so everyone discussing it later sees the same number.
FAQ
How do the 24 map to the 8 compass points?
N is Zi, NE is Gen, E is Mao, SE is Xun, S is Wu, SW is Kun, W is You and NW is Qian. Each 45° compass point holds three of the 24 sectors.
What if the reading sits on a boundary?
Phone compasses wobble by a few degrees near metal. Within ±3° of a boundary, measure again from another spot or compare with the plan.
Compass Camera
No sign-up, no location permission, and your photos stay on your phone. Free on Android.