Convert a measured slope distance to horizontal distance.
D = L·cos(α),α 为竖直角。
| Item | Formula / Note | Source / Standard |
|---|---|---|
| Slope-to-horizontal reduction | Horizontal distance S = D · cos(alpha), where alpha is the vertical angle | GB 50026-2020, Code for engineering surveying |
| Using the zenith distance | S = D · sin Z, where Z is the zenith distance | GB 50026-2020, Code for engineering surveying |
| Height difference | h = D · sin(alpha) = D · cos Z | GB 50026-2020, Code for engineering surveying |
| Instrument corrections | Distances require meteorological, additive-constant and scale-constant corrections | GB 50026-2020, Code for engineering surveying |