During the orientation of a plane table, the process involves sighting various points to establish reference lines and angles. The orientation is crucial in ensuring accurate measurements and mapping. There are several methods to orient a plane table, but in this particular scenario, we will discuss three common sighting techniques: sighting the farthest point, sighting the nearest point, and sighting the previous station.

1. Sighting the Farthest Point:
When orienting a plane table, one method is to sight the farthest visible point from the current station. This point should be at a considerable distance, ensuring accuracy in measuring angles and distances. By aligning the plane table with this farthest point, a reference line is established. This sighting technique is commonly used in open areas or when there are no prominent nearby objects for orientation.

2. Sighting the Nearest Point:
Alternatively, the nearest visible point from the current station can be sighted for orientation. This point should be relatively closer to the plane table and easily identifiable. By aligning the plane table with this nearest point, another reference line is established. This method is useful when there are nearby objects or landmarks that can serve as reliable reference points.

3. Sighting the Previous Station:
In some cases, it may be necessary to sight the previous station to establish the orientation of the plane table. This is particularly important when conducting a traverse or when working on a surveying project that requires a continuous connection between stations. By aligning the plane table with the previous station, the reference line can be extended, ensuring consistency in measurements and mapping.

It is worth noting that the choice of which point to sight during orientation depends on the specific situation, available reference points, and the accuracy required for the survey. The farthest point is often preferred when working in open areas, while the nearest point or the previous station may be more suitable in areas with prominent objects or when working on a traverse.

In conclusion, during the orientation of a plane table, the farthest point, nearest point, or the previous station can be sighted to establish reference lines and angles. The choice of which point to sight depends on the specific circumstances and the accuracy requirements of the survey.