Distance By Sea Calculator

Great Circle Formula:

\[ d = R \times \arccos[\sin(\phi_1) \times \sin(\phi_2) + \cos(\phi_1) \times \cos(\phi_2) \times \cos(\Delta\lambda)] \]

Port 1 Latitude:

Port 1 Longitude:

Port 2 Latitude:

Port 2 Longitude:

Maritime Distance:

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1. What is the Great Circle Distance?

The Great Circle Distance is the shortest distance between two points on the surface of a sphere, following the curvature of the Earth. For maritime navigation, this represents the most efficient route between two ports.

2. How Does the Calculator Work?

The calculator uses the Great Circle Formula:

\[ d = R \times \arccos[\sin(\phi_1) \times \sin(\phi_2) + \cos(\phi_1) \times \cos(\phi_2) \times \cos(\Delta\lambda)] \]

Where:

\( d \) — Distance in nautical miles
\( R \) — Earth's radius (3443.92 nautical miles)
\( \phi_1, \phi_2 \) — Latitudes of port 1 and port 2 in radians
\( \Delta\lambda \) — Difference in longitude between ports in radians

Explanation: The formula calculates the central angle between two points on a sphere and converts it to distance using the Earth's radius.

3. Importance of Maritime Distance Calculation

Details: Accurate maritime distance calculation is essential for voyage planning, fuel estimation, ETA calculations, and optimizing shipping routes to reduce costs and transit times.

4. Using the Calculator

Tips: Enter latitude and longitude coordinates for both ports in decimal degrees. Latitude ranges from -90° to 90°, longitude from -180° to 180°. Positive values for North/East, negative for South/West.

5. Frequently Asked Questions (FAQ)

Q1: What is a nautical mile?
A: A nautical mile is approximately 1.852 kilometers or 1.15078 statute miles, based on one minute of latitude.

Q2: Why use Great Circle instead of Rhumb Line?
A: Great Circle provides the shortest distance, while Rhumb Line maintains constant bearing but is longer for long distances.

Q3: How accurate is this calculation?
A: The calculation provides theoretical shortest distance. Actual sailing routes may vary due to weather, currents, and navigational constraints.

Q4: Can I use this for air navigation?
A: Yes, the Great Circle formula is also used in aviation for calculating the shortest routes between airports.

Q5: What about port approach and departure?
A: This calculates point-to-point distance. Actual voyage distance includes approach channels, port maneuvers, and navigational deviations.