Distance Between Two
    Points
 Pacing
 Chaining
 Temperature
 Standardisation
 Catenary
 Slope
 Tension
 Tachaeometry
 Stadia System
 Measurement of
    Tacheometric Constants
 Refraction and Curvature
 Theodolite
    Tachaeometry
 Field Tachaeometry
 Electronic Tachaeometry

Slope

All plan distances are always quoted as horizontal distances, therefore any distancenot measured on the horizontal will need to be corrected for slope. Slope correction must always be considered, and either eliminated in the field or mathematically compensated.

1. Reduction by slope angle

   The horizontal distance is given by L = lcosb

2. Reduction by differences in height

   L = (l² - Dh²)^1/2