Distance Calculator

Distance Calculator

Distance in Coordinate Systems

1. 2D Coordinate Plane Distance

The distance between two points (x1,y1)(x1​,y1​) and (x2,y2)(x2​,y2​) is calculated using the Euclidean distance formula:d=(x2−x1)2+(y2−y1)2d=(x2​−x1​)2+(y2​−y1​)2​. Distance Calculator

Key Notes:

  • The order of points does not affect the result (the formula is commutative).
  • Example: For (1,5)(1,5) and (3,2)(3,2):d=(3−1)2+(2−5)2=4+9=13d=(3−1)2+(2−5)2​=4+9​=13​

2. 3D Coordinate Space Distance

The distance extends to 3D for points (x1,y1,z1)(x1​,y1​,z1​) and (x2,y2,z2)(x2​,y2​,z2​):d=(x2−x1)2+(y2−y1)2+(z2−z1)2d=(x2​−x1​)2+(y2​−y1​)2+(z2​−z1​)2​

Example: For (1,3,7)(1,3,7) and (2,4,8)(2,4,8):d=12+12+12=3d=12+12+12​=3​


3. Distance on Earth’s Surface

For real-world applications, Earth’s curvature requires spherical or ellipsoidal models. Two common methods:

A. Haversine Formula

Calculates great-circle distance (shortest path on a sphere) between two points given their latitudes (ϕ1,ϕ2)(ϕ1​,ϕ2​) and longitudes (λ1,λ2)(λ1​,λ2​):d=2r⋅arcsin⁡(sin⁡2(Δϕ2)+cos⁡ϕ1cos⁡ϕ2sin⁡2(Δλ2))d=2r⋅arcsin(sin2(2Δϕ​)+cosϕ1​cosϕ2​sin2(2Δλ​)​)

  • rr: Earth’s radius (~6,371 km).
  • Δϕ=ϕ2−ϕ1Δϕ=ϕ2​−ϕ1​, Δλ=λ2−λ1Δλ=λ2​−λ1​ (in radians).
  • Limitation: ~0.5% error due to Earth’s ellipsoidal shape.
B. Lambert’s Formula

More precise for Earth’s ellipsoid, with ~10-meter accuracy over long distances:d=a(σ−f(X+Yσ))d=a(σf(X+))

  • aa: Equatorial radius (6,378 km).
  • σσ: Central angle (computed via auxiliary formulas).
  • ff: Earth’s flattening (~1/298.257).
  • X,YX,Y: Terms involving reduced latitudes β1,β2β1​,β2​.

Note: Both formulas approximate Earth’s irregular surface but are sufficient for most practical purposes.


When to Use Which?

  • 2D/3D Euclidean: Flat geometries (e.g., maps, grids).
  • Haversine: Spherical Earth models (short-medium distances).
  • Lambert’s: High-precision or global-scale calculations.

Let me know if you’d like further refinements!