## Plane Table Survey
Main Principles of Plane Table Survey (2.5–3 marks)
The plane table survey is based on the following principles:
1. Parallelism (Orientation)
- The position of objects on the map is obtained by drawing lines parallel to the directions of objects on the ground.
- Proper orientation ensures that plotted lines represent true ground directions.
2. Radiation Principle
- From a single station, lines are drawn to various points.
- The distances are measured and plotted to scale.
3. Intersection Principle
- The position of a point is fixed by the intersection of two rays drawn from two known stations.
4. Traversing Principle
- A series of connected points are plotted by moving the table from one station to another.
Advantages of Plane Table Survey (2–3 marks)
- Fieldwork and plotting are done simultaneously → saves time
- No need for field book → reduces recording errors
- Errors can be detected and corrected on the spot
- Simple equipment and easy to use
- Suitable for small-scale and detailed surveys
Disadvantages of Plane Table Survey (2–3 marks)
- Not suitable for high precision work
- Cannot be used in bad weather (rain, wind)
- Requires clear visibility of points
- Equipment is bulky and difficult to handle
- Not suitable for large areas
Conclusion (1 mark)
Plane table surveying is based on graphical representation and orientation principles, offering quick and simple fieldwork, but it is limited in accuracy and weather conditions.
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