How to Use the Compass

1What this compass does

It is a live bearing compass: it tells you which direction you are facing right now, and translates that bearing into the twenty-four mountains and eight palaces used in traditional feng shui. Hold the phone flat, screen up — the needle points where you are facing.

It is not an automatic house-orientation tool, and this point matters. Facing direction requires first fixing the centre of the property, then sighting the main door from that centre. A casual reading taken anywhere indoors measures you, not the house. What this compass gives you is a reliable angular baseline, so that measuring a door, a stove or the head of a bed is no longer guesswork.

• What it measures: your true-north bearing to 0.1°, the corresponding mountain (each 15°), palace (each 45°) and compass point.
• What it does not measure: the house facing, its fortunes, or your personal kua. Those come from the six schools under Property Analysis; the compass only supplies the angle.
• Where to find it: inside Today’s Directions, directly beneath the nine-palace chart. It works best on a phone; desktop browsers fall back to manual mode for hardware reasons, explained in section 6.

2Reading the dial

The dial is built in concentric bands. Match the numbers on the diagram to the notes below.

• ① Tick ring (outermost): a tick every 15°; the ones at the exact palace centres (0°, 45°, 90°…) are longer and darker for quick alignment.
• ② Twenty-four mountains: twenty-four cells of 15° each, labelled with a stem, branch or trigram. Zi sits at 0° (due north); clockwise: Gui, Chou, Gen, Yin, Jia, Mao and so on. Palace by palace: Kan holds Ren-Zi-Gui, Gen holds Chou-Gen-Yin, Zhen holds Jia-Mao-Yi, Xun holds Chen-Xun-Si, Li holds Bing-Wu-Ding, Kun holds Wei-Kun-Shen, Dui holds Geng-You-Xin, and Qian holds Xu-Qian-Hai.
• ③ Eight palaces: eight sectors of 45° in the Later Heaven arrangement, with Kan (due north) centred on 0°. Palaces are the coarser layer — saying "the south side" is easier to act on than "the Wu mountain".
• ④ The fixed needle: the red tip always points up. This is deliberate — a real compass needle also points north while the housing turns. The dial rotates under a stationary needle, so the current bearing is always brought to the top where your eye already is.
• ⑤ The highlighted wedge: a pale gold sector swept clockwise from the top (the needle) to the current reading, closed by a thin cinnabar line. It shows at a glance how far you have turned from north; a larger angle, a wider wedge.

3How to read the numbers

The readout sits beside the dial. Facing due north, it looks like this:

• The large 0.0° — the true-north bearing: 0° north, 90° east, 180° south, 270° west, increasing clockwise.
• N · Kan · Zi — three levels of granularity, coarse to fine. N is the compass point (plain speech), Kan is the Later Heaven palace (45°), Zi is the mountain (15°, the finest — this is what chart calculations use).
• Magnetic bearing / True bearing / Declination — three small rows. The magnetic row is the raw sensor value, the true row is the corrected result, and declination is the difference. In manual mode the magnetic row is absent: dragging sets a true bearing directly, so there is no uncorrected raw value to show.

4Three ways to use it

In order of reliability: the phone sensor is most accurate, manual dragging is most dependable, and calibration rescues devices whose heading is not absolute. They mix freely — if the sensor drifts, just drag to take over.

1. 1

   Phone sensor (first choice)

   Open Today’s Directions on the phone and tap Enable compass. On iOS 13 and later the permission must be triggered by that tap; the browser will show a system dialog — choose Allow. The button then reads Sensor active and the dial turns with you in real time.
   The reading is absolute: no figure-of-eight needed before it settles — just raise the phone and read. Stop sensor switches it off to save battery.
2. 2

   Drag or arrow keys

   Works everywhere, and is the only mode on desktop. Drag the dial, or focus it and nudge with ← → for 5° steps. Hold Shift for 15° steps — exactly one mountain, handy for hopping to a neighbouring sector.
   Manual mode suits the case where you already know the angle and want to see which mountain and palace it falls in: reading a floor plan, or checking a facing given in a case study.
3. 3

   Set current as north

   Appears only while the sensor runs. A minority of browsers expose only a relative heading (the alpha zero point is randomised each time), which adds a fixed offset to every reading. The fix: stand still, aim the phone at a known bearing (say the main door is known to face south — aim at south), then tap Set current as north. The offset is recorded and subtracted from every later reading.
   Calibration persists for the session, so it is a one-off per session. Redo it after moving to a different location or restarting the browser.

5Why the reading is corrected

A compass points at magnetic north, not the true north on a map. The geomagnetic pole and the geographic pole do not coincide; the angle between them is declination. It varies with position and drifts slowly with the years — around −7° in Beijing, near zero in London, noticeably east on the North American west coast.

How much is 7°? One mountain spans 15°, so 7° is roughly half a mountain. Uncorrected, a reading can land in the wrong mountain — a bearing that belongs in Zi (within 15° of north) shows up as Ren or Gui instead. In chart work, one sector off is a different chart entirely.

The compass embeds the World Magnetic Model (WMM), a 12th-order spherical harmonic expansion. It computes declination in real time for your coordinates and converts the magnetic reading into a true bearing. That is why the "magnetic" and "true" rows differ slightly, and why the "declination" row shows exactly that difference.

Feng shui orients to true north, and this is the settled convention: compass corrections, plan north and satellite azimuth all reference true north, and only true north is directly comparable with records made a century ago. So the large figure is already a true bearing — take it and use it.

6Getting a steadier reading

Phones read a magnetometer, and any magnetic field disturbs it. Work through these in order and you can usually keep the error inside a degree.

• Keep clear of magnets: magnetic phone cases, magnetic clasps, metal desk edges, laptops, speakers, fridge doors and rebar in walls are the usual culprits. Stay at least 30 cm away while measuring, and further beside metal door frames.
• Wave a figure of eight: magnetometers accumulate bias over time and the whole reading drifts. Slowly trace a few figure-eights in the air to let the system recalibrate — it is a built-in routine and takes effect immediately.
• Keep it level: hold the phone flat, screen up. Tilting still works but costs accuracy. When sighting a door, stand just inside it and extend the phone at chest height rather than holding it up in front of your eyes.
• Let it settle: the first few seconds after enabling the sensor are a normal convergence period. Wait until the number stops moving, then take two or three readings from the same spot and keep the value that agrees.
• Cross-check: compare against the system compass app. A 1–2° gap is normal — different models and algorithms. A larger gap means an interference source is still in play, or a calibration is due.

7Common questions