Correct Answer - Option 3 : astronomical observations
Concept:
Traversing:
Traversing is the type of survey in which a number of connected survey lines form the framework and the directions and lengths of the survey lines are measured with the help of an angle measuring instrument and tape or chain respectively.
Types of Surveying:
There are two types of traverse surveying. They are:
-
Closed traverse: When the lines form a circuit that ends at the starting point, it is known as a closed traverse.
-
Open traverse: When the lines form a circuit that ends elsewhere except the starting point, it is said to be an open traverse.
Check on an open traverse:
In open traverse, the measurements can not be checked directly. But some field measurements can be taken to check the accuracy of the work. The methods are-
1). Taking cut-off lines
2). Taking an auxiliary point
3). Astronomical observations
Note:
Astronomical observations:
It is the practice and study of observing celestial objects with the use of telescopes and other astronomical instruments. As a science, the study of astronomy is somewhat hindered in that direct experiments with the properties of the distant universe are not possible.
