Distance By Sea Calculator Australia

Great Circle Distance Formula:

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

Latitude 1:

degrees

Longitude 1:

degrees

Latitude 2:

degrees

Longitude 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 most efficient sea route between two locations.

2. How Does the Calculator Work?

The calculator uses the Great Circle Distance 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 (3440.065 nautical miles)
\( \phi_1, \phi_2 \) — Latitude of points 1 and 2 in radians
\( \Delta\lambda \) — Difference in longitude between two points in radians

Explanation: The formula calculates the central angle between two points and multiplies by the Earth's radius to get the distance.

3. Importance of Sea Distance Calculation

Details: Accurate sea distance calculation is crucial for maritime navigation, voyage planning, fuel estimation, and logistics in Australian waters and beyond.

4. Using the Calculator

Tips: Enter latitude and longitude coordinates in decimal degrees. Valid ranges: Latitude (-90 to 90), Longitude (-180 to 180). Australian coordinates are typically negative for latitude (south) and positive for longitude (east).

5. Frequently Asked Questions (FAQ)

Q1: Why use nautical miles for sea distance?
A: Nautical miles are the standard unit for maritime and aviation navigation because they correspond to one minute of latitude (1 nautical mile = 1.852 km).

Q2: How accurate is the great circle distance?
A: The calculation provides the theoretical shortest distance. Actual sailing routes may vary due to currents, winds, and navigational constraints.

Q3: What are typical Australian port coordinates?
A: Sydney: -33.86, 151.21; Melbourne: -37.81, 144.96; Brisbane: -27.47, 153.03; Perth: -31.95, 115.86

Q4: Does this account for Earth's oblateness?
A: The calculation assumes a spherical Earth. For higher precision, ellipsoidal models like Vincenty's formulae could be used.

Q5: Can I use this for air distance as well?
A: Yes, great circle distance is also used for calculating the shortest air route between two points.