Differential leveling is the process of measuring vertical distances from a known elevation point to determine elevations of unknown points. In this process number of inter stations are located and instrument is shifted to each station and observed the elevation of inter station points. Finally difference between original two points is determined.
In field it is difficult to carry data book along with instruments. Further manual calculations are done to make entry in the data book. Reduce the effort of manual calculations to obtain directly the Reduced Levels (RL) of various points.