A Brief Analysis of the Influence of "Earth Curvature" and "Vertical Atmospheric Refraction" of Trigonometric Leveling

Trigonometric leveling is an indirect method,which is fast in surveying and not affected by the topographic undulation.It finishes elevation surveying in the process of positioning the control points.Trigonometric leveling is affected by earth curvature and atmospheric refraction,earth curvature reduces the value of the elevation surveying result while atmospheric refraction enlarges it.Trigonometric leveling using total station bilateral observation,which raises the height of visual line,calculates elevation using short side transference and observes at stable weather to reduce the affection of refraction,improves the accuracy of trigonometric leveling.