Correct Answer - Option 4 : Reconnaissance
Concept:
Traversing:
- The traversing in which the traverse legs are measured by direct chaining on the ground and the traverse angle at every traverse station is measured with a theodolite is known as theodolite traversing.
The procedure of Traverse:
The following steps are required to establish a traverse:
1. Reconnaissance
- Reconnaissance is the preliminary field inspection of the entire area to be surveyed.
- During reconnaissance, Surveyor goes to the field, checks the entire area, and decides the best plan of working.
He has to see the suitability and intervisibility of traverse stations. Also, he has to decide which method of traversing will be employed and accordingly, the instruments and accessories that may be necessary.
2. Selection of Traverse Stations
- The basic principle of a survey, i.e., working from whole to the part should be adopted. A minimum number of stations should be selected.
- The length of traverse lines is as long as possible to reduce the time and centering effect of the stations. It is better to select stations on a level and firm ground. After the selection of stations, they are marked with pegs.
3. Linear and Angular Measurements
- Distances between stations are measured by tape or chain, or tacheometric method or electric distance measurings (EDM) instruments like geodimeter.
- Angular measurements are done by prismatic compass or theodolite.
4. Plotting of Traverse Survey
There are two methods of plotting a traverse survey. The methods are as follows:
(a) Distance and Angle Method In this method
- Distances between stations are laid off to scale and included angles or bearings are plotted by protector or tangent of angle or chord of the angle.
(b) Co-ordinate Method
- In this method, survey stations are plotted by calculating their coordinates. This method is more practical and accurate. The biggest advantage of this method of plotting is that closing errors can be eliminated by balancing.
