Overview of Leveling Techniques and Instruments
Leveling is a fundamental technique used in surveying and engineering to determine the relative heights or elevations of different points on the Earth’s surface. The primary objective of leveling is to establish a level or horizontal line of sight, which serves as a reference for measuring vertical distances.
Types of Levels and Staffs
A level is an optical instrument used in conjunction with a levelling staff to establish the relative heights levels of objects or marks. Levels include the dumpy level, Y level, Cushing’s level, tilting level, and automatic level. Levelling staves may be divided into two classes: self-reading and non-self-reading.
Differentiation in Leveling Techniques
Based on the observation points and instrument positions, direct leveling is divided into simple, differential, and precise leveling. Simple leveling consists of calculating the difference in the elevation between two points. Differential leveling determines the relative heights of objects. Precise leveling determines the absolute height of objects.
Understanding Level Surfaces in Surveying
A level surface is defined as a curved surface which at each point is perpendicular to the direction of gravity at the point. The surface of still water is a truly level surface. Any surface parallel to the mean spheroidal surface of the Earth is, therefore, a level surface.
Significance of Leveling in Surveying and Engineering
Leveling helps surveyors make contour maps of land or sea surfaces. It helps in laying the ground level for building structures and aids transport engineers in ensuring the appropriate slope for liquid movement.