Object and Uses of Surveying
As stated in the definition, object of surveying is to show relative positions of various objects of an area on […]
Surveying
Surveying is the art of making measurements of objects on, above or beneath the ground to show their relative positions on paper. The relative position required is either horizontal, or vertical, or both. Less precisely the term Surveying is used to the measurement of objects in their horizontal positions. Measurements to deteremine their relative vertical positions is known as levelling.
Obstacles in Chaining
Though it is desirable to select stations so as to avoid obstacles, occasionally the obstacles are unavoidable. Various obstacles to
Object and Uses of Levelling
As stated in the definition of levelling, the object is (i) to determine the elevations of given points with respect
Methods of Plane Tabling
The following four methods are available for carrying out plane table survey: 1. Radiation 2. Intersection 3. Traversing 4. Resection.
Method of Using a Compass
To take a reading from a compass, the following temporary adjustments are required: (i) Centring: The compass should be fixed
Methods of Levelling
The following methods are used to determine the difference in elevation of various points: (i) Barometric levelling (ii) Hypsometric levelling
Methods of Linear Measurements
Various methods used for linear measurements may be grouped as: (i) Approximate (ii) Using chain or tape (iii) By optical
Methods of Contouring
Contouring needs the determination of elevation of various points on the ground and at the same the horizontal positions of
Map projections
9.1 Categories and properties of projections Chapter 8 has shown that it is useful to express the 3D positions of