Method of Plane Tabling for Establishing Instrument Station

The method of plane tabling is a surveying technique that involves using a plane table to create a map of a specific area. This technique is commonly used to establish instrument stations for surveying purposes. There are several methods that can be used to establish an instrument station, but the most commonly used method is resection.

Resection Method

The resection method involves using the plane table to locate the position of the instrument station by sighting on at least two known points. The steps involved in using the resection method to establish an instrument station are as follows:

1. Set up the plane table at a location that is visible from all the known points.

2. Level the table and orient it so that one edge is aligned with a north-south line.

3. Sight on the first known point and mark its position on the table by placing a pin or nail in the table.

4. Sight on the second known point and mark its position on the table in the same way.

5. Draw lines on the table connecting the known points to the new point, which is the location of the instrument station.

6. Measure the angles between the lines and record them.

7. Calculate the coordinates of the new point using triangulation or other methods.

Advantages of Resection Method

The resection method has several advantages over other methods of establishing instrument stations. These advantages include:

1. It is quick and easy to set up and use.

2. It does not require the use of additional equipment, such as tripods or stadia rods.

3. It can be used in areas where other methods may not be practical, such as in dense vegetation or on steep slopes.

Conclusion

In conclusion, the resection method is the most commonly used method of establishing instrument stations using the plane tabling technique. This method involves sighting on at least two known points and using triangulation to calculate the position of the new point, which is the location of the instrument station. The resection method is quick, easy, and does not require additional equipment, making it a popular choice for surveyors.