Surveying

Introduction

     The art of determining relative positions of objects on the surface of earth by taking measurements in the horizontal and vertical planes, is called surveying. The surveying may primarily be divided into the following two classes:

      1. Plane Surveying : The surveys in which the curvature of earth is not taken into consideration are known as plane surveys. These surveys extend over small areas. The degree of accuracy obtained in this type of surveying is comparatively low(generally areas less than 250 km²).

      2. Geodetic Surveying : The surveys in which the curvature of earth is taken into consideration are known as geodetic surveys (also called trigonometrical surveying). These surveys extend over large areas (more than 250 km²) and where the degree of accuracy required is great.