Explanation:

In plane table surveying, the plane table is a fundamental tool used to measure angles and distances on the field, and then plot them directly onto a paper or drawing sheet. The method of orientation refers to the process of aligning the plane table with the known points or features on the map.

When the plane table is not yet located on the map, the process of orienting it and determining its position is called resection. This method involves sighting known points or features in the field and then plotting them on the map to determine the position of the plane table.

Steps in Resection Method:

1. Selecting Known Points: In the resection method, at least two known points on the map should be selected. These points should also be visible from the field where the plane table is located.

2. Setting up the Plane Table: The plane table is set up at the desired location in the field. It should be placed on a stable and level surface.

3. Orienting the Alidade: The alidade is the sighting device attached to the plane table. It is used to measure angles and sight the known points. The alidade is oriented by aligning it with the magnetic north or a reference azimuth.

4. Sighting the Known Points: Using the alidade, the known points selected earlier are sighted in the field. The sighted points should be clearly marked on the map using a pencil or a pin.

5. Drawing Lines of Sight: Lines of sight are drawn from the location of the plane table to the sighted points on the map. These lines represent the direction of the known points with respect to the plane table.

6. Intersection of Lines: The intersection of two or more lines of sight on the map gives the approximate location of the plane table. This intersection point can be marked as the new position on the map.

7. Adjustments: If the intersection point does not align with the desired position or if the lines of sight do not intersect accurately, adjustments can be made by re-orienting the alidade and repeating the sighting process.

By using the resection method, the plane table can be accurately positioned on the map even if its location is not yet known. This method allows surveyors to plot field observations and measurements onto the map, facilitating the creation of an accurate survey plan.