Nautical Distance Between Ports Calculator

Great Circle Distance Formula:

\[ d = \arccos(\sin(lat1) \times \sin(lat2) + \cos(lat1) \times \cos(lat2) \times \cos(lon2-lon1)) \times 3440 \]

Port 1 Latitude:

degrees

Port 1 Longitude:

degrees

Port 2 Latitude:

degrees

Port 2 Longitude:

degrees

Nautical Distance:

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1. What is Nautical Distance?

Nautical distance is the shortest path between two points on the surface of a sphere (great-circle distance). It's essential for marine navigation, flight planning, and geographic calculations.

2. How Does the Calculator Work?

The calculator uses the Great Circle Distance formula:

\[ d = \arccos(\sin(lat1) \times \sin(lat2) + \cos(lat1) \times \cos(lat2) \times \cos(lon2-lon1)) \times 3440 \]

Where:

\( lat1, lat2 \) — Latitude coordinates of both ports (degrees)
\( lon1, lon2 \) — Longitude coordinates of both ports (degrees)
3440 — Radius of the Earth in nautical miles (mean value)

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 Nautical Distance Calculation

Details: Accurate distance calculation is crucial for voyage planning, fuel estimation, ETA calculations, and safety of navigation.

4. Using the Calculator

Tips: Enter coordinates in decimal degrees (positive for North/East, negative for South/West). For example, New York is approximately 40.7128° N, 74.0060° W.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between nautical miles and statute miles?
A: 1 nautical mile = 1.15078 statute miles = 1.852 kilometers. Nautical miles are based on Earth's circumference.

Q2: How accurate is this calculation?
A: It provides theoretical great-circle distance. Actual sailing distance may differ due to currents, winds, and obstacles.

Q3: Can I use this for flight distance?
A: Yes, the same formula works for air navigation, though flight paths may be adjusted for winds and airspace restrictions.

Q4: What coordinate format should I use?
A: Decimal degrees are recommended (e.g., 34.0522° instead of 34° 3' 8"). Convert DMS to decimal if needed.

Q5: Why does the Earth's radius vary?
A: Earth is an oblate spheroid, with equatorial radius about 3443.9 NM and polar radius about 3432.4 NM. We use the mean value.