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. This calculator computes the distance between two latitude/longitude points on Earth using the Haversine formula.

2. How Does the Calculator Work?

The calculator uses the Haversine formula:

Where:

• 6371 — Earth's radius in kilometers
• lat1, lat2 — Latitude of points 1 and 2 (in radians)
• lon1, lon2 — Longitude of points 1 and 2 (in radians)
• arccos — Inverse cosine function

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

3. Importance of Accurate Distance Calculation

Details: Accurate distance calculation is crucial for navigation, flight planning, logistics, and geographical analysis. The great-circle distance provides the most accurate measurement for global distances.

4. Using the Calculator

Tips: Enter latitude and longitude in decimal degrees (e.g., 40.7128° N = 40.7128, 74.0060° W = -74.0060). Positive values for North/East, negative for South/West.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this calculation?
A: The Haversine formula is accurate to about 0.3% for most practical purposes on Earth.

Q2: Why not use simple Euclidean distance?
A: Euclidean distance doesn't account for Earth's curvature and becomes increasingly inaccurate over long distances.

Q3: What's the maximum distance this can calculate?
A: Theoretically up to half Earth's circumference (~20,037 km), but practical limits depend on coordinate precision.

Q4: Can I use this for other planets?
A: Yes, but you'd need to substitute the correct planetary radius (6371 km is Earth's mean radius).

Q5: How does altitude affect the calculation?
A: This calculation ignores altitude differences and computes surface distance only.