Distance Calculator By Sea

Great Circle Distance Formula:

\[ \text{sea\_dist} = \text{great\_circle\_distance}(lat1, lon1, lat2, lon2) \]

Latitude Point 1:

degrees

Longitude Point 1:

degrees

Latitude Point 2:

degrees

Longitude Point 2:

degrees

Sea Distance:

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1. What is Great Circle Distance?

The great-circle distance is the shortest distance between two points on the surface of a sphere, measured along the surface of the sphere. For maritime navigation, this represents the shortest sea route between two locations.

2. How Does the Calculator Work?

The calculator uses the Haversine formula:

\[ d = 2r \cdot \arcsin\left(\sqrt{\sin^2\left(\frac{\Delta\phi}{2}\right) + \cos\phi_1 \cdot \cos\phi_2 \cdot \sin^2\left(\frac{\Delta\lambda}{2}\right)}\right) \]

Where:

\( d \) — Distance between points
\( r \) — Earth's radius (3440.065 nautical miles)
\( \phi \) — Latitude in radians
\( \lambda \) — Longitude in radians
\( \Delta\phi \) — Difference in latitudes
\( \Delta\lambda \) — Difference in longitudes

Explanation: The formula accounts for the spherical shape of the Earth to calculate the shortest path between two points.

3. Importance of Sea Distance Calculation

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

4. Using the Calculator

Tips: Enter coordinates in decimal degrees (e.g., 34.0522 for latitude, -118.2437 for longitude). Positive values for North/East, negative for South/West.

5. Frequently Asked Questions (FAQ)

Q1: Why use nautical miles for sea distance?
A: Nautical miles (nm) are the standard unit of measurement in maritime and aviation navigation, equal to one minute of latitude.

Q2: How accurate is this calculation?
A: The calculation assumes a perfect sphere. Actual distances may vary slightly due to Earth's ellipsoidal shape and local topography.

Q3: What's the maximum distance that can be calculated?
A: The formula works for any two points on Earth, including antipodal points (~12,429 nm).

Q4: Can I use this for air distance as well?
A: Yes, great circle distance applies to both sea and air navigation as the shortest path between points.

Q5: How does this differ from rhumb line distance?
A: Great circle is the shortest path but requires constant course changes. Rhumb line maintains constant bearing but is longer.