Compare great-circle and rhumb-line distance between two points - the standard ocean-passage routing decision.
Formula
$$ d_{gc} = R \arccos(\sin\phi_1 \sin\phi_2 + \cos\phi_1 \cos\phi_2 \cos(\Delta\lambda)) $$Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $\phi_1, \phi_2$ | Latitudes | deg | chart |
| $\Delta\lambda$ | Difference of longitude | deg | chart |
Sources
- Bowditch Pub.9 Ch.24.