This concept covers levelling procedures in surveying: the field methods (height-of-instrument and rise-and-fall) for determining reduced levels (RL) of points from a horizontal line of sight, using back sight, intermediate sight, and foresight observations referenced to a benchmark and propagated through turning/change points. It also formalizes error theory for levelling networks—natural error sources, arithmetic checks on computed observations, and an acceptable misclosure error criterion relating permissible closing error to survey distance or number of instrument settings—along with classification of specialized levelling types (reciprocal, profile, cross-sectioning, precise) defined by the geometric or precision challenge each addresses. It belongs to surveying/geomatics, specifically vertical control and elevation determination, extending the prior theory of balanced back sight/foresight observation to eliminate systematic instrument and atmospheric errors.
This concept covers levelling procedures in surveying: the field methods (height-of-instrument and rise-and-fall) for determining reduced levels (RL) of points from a horizontal line of sight, using …