Compass Rule vs Transit Rule Comparison
A free, browser-based tool. Runs entirely in your browser — no sign up, nothing stored.
Traverse legs
| Bearing (DD) | Distance (m) | |
|---|---|---|
Bearings are whole-circle (0–360°, clockwise from north). Runs in your browser.
Bowditch vs Transit adjustment
| Bearing | Bowditch ΔLat | Bowditch ΔDep | Transit ΔLat | Transit ΔDep |
|---|---|---|---|---|
| 0° | 100.000 | -0.251 | 100.000 | 0.000 |
| 90° | 0.000 | 99.749 | 0.000 | 99.497 |
| 180° | -100.000 | -0.251 | -100.000 | 0.000 |
| 270° | -0.000 | -99.248 | -0.000 | -99.497 |
The compass (Bowditch) rule spreads the misclose in proportion to leg length; the transit rule spreads it in proportion to each leg’s |latitude| / |departure|. Both close the traverse — “max method difference” is how far their adjusted coordinates differ.
How to use this calculator
- Pick your bearing format (DD, DMS or DDM) and enter each leg's whole-circle bearing and distance.
- Add or remove legs to match your closed traverse.
- Read the misclose, then the latitudes and departures adjusted by both the compass (Bowditch) and transit rules side by side.
How it works
Both rules remove the linear misclose so the traverse closes, but they distribute it differently. The compass (Bowditch) rule corrects each leg in proportion to its length; the transit rule corrects each leg in proportion to its |latitude| (for the latitude correction) and |departure| (for the departure correction).
The Bowditch rule is the usual default. The transit rule is sometimes used when the angles are considered more reliable than the distances. The tool shows how far the two methods' adjusted coordinates end up apart.
Worked example
A four-leg loop with a 1 m departure misclose. Both rules close the traverse, but the transit rule loads more of the correction onto the long east–west legs (largest |departure|), so the adjusted coordinates differ slightly from the Bowditch result.
Frequently asked questions
Which rule should I use?
The compass (Bowditch) rule is the common default and assumes angles and distances are about equally reliable. The transit rule weights by latitude/departure and is sometimes preferred when the angles are more reliable than the distances. Follow your brief.
Why do the two methods give different coordinates?
They both remove the same misclose, but spread it differently — by length (Bowditch) versus by |lat|/|dep| (transit). The 'max method difference' shows how far apart the adjusted stations end up.
Is this official course material?
No. It is free study support mapped to surveying course levels — not official North Metropolitan TAFE content or advice. Always follow your lecturer and the official assessment brief, and check your own working.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.