Compute the horizontal distance between two points from their plane coordinates.
输入两点平面坐标 (x₁,y₁) 与 (x₂,y₂),求水平距离。
| Item | Formula / Note | Source / Standard |
|---|---|---|
| Plane distance | D = √(Δx² + Δy²) from coordinate differences | Basic analytic geometry |
| Gauss distortion | Length distortion grows from the central meridian, up to 0.1–1 m per km | GB 50026-2020 distortion control |
| Reduction to grid | D_grid = D_ground × (1 + y²m ÷ (2R²)) with R = 6371 km | Control-network reduction practice |
| Azimuth linkage | Distance and azimuth combine as Δx = D·cosα, Δy = D·sinα | Traverse computation rules |