Getting Accurate Orientation in Plane Tabling

Plane tabling is a method of surveying, where a plane table is used to make measurements and draw a map of the survey area. Accurate orientation is essential in plane tabling to ensure accurate measurements. Among the various procedures used in plane tabling, resection is considered the most distinctive feature.

Resection Procedure

The resection procedure involves setting up the plane table at an unknown point and sighting on at least three known points. The known points should be visible from the unknown point and their positions should be accurately known. The orientation of the table is then adjusted until the lines of sight of the known points intersect at the same point on the table. The intersection point is the unknown point.

Advantages of Resection

1. No Backsighting Required: One of the advantages of the resection method is that no backsighting is required. This means that the surveyor does not have to move to another location to obtain an accurate orientation.

2. Useful in Inaccessible Areas: Resection is particularly useful in areas where it is difficult to access all the points from one location. For example, in hilly or mountainous areas, it may be difficult to see all the points from one location.

3. Time-Saving: Resection is a time-saving method since it allows the surveyor to obtain an accurate orientation quickly.

Conclusion

Accurate orientation is essential in plane tabling to ensure accurate measurements. Resection is considered the most distinctive feature of plane tabling since it allows the surveyor to obtain an accurate orientation without the need for backsighting. It is particularly useful in inaccessible areas and saves time.