Aquaculture Engineering (2+1)

Unit 1- Surveying

Compass surveying

Introduction

Chain surveying can be used when the area to be surveyed is comparatively small and is fairly flat. However, when large areas are involved methods of chain surveying alone are not sufficient and convenient. In such cases it becomes essential to use some sort of instruments which enables angles or direction of survey lines to be observed. In engineering practice, following are the instruments used for the measurements.

Instruments for the direct measurement of direction

• Surveyor’s compass
• Prismatic compass

Instruments for measurement of angles

• Sextant
• Theodolite