There are two basic principles of surveying.
1. Work from whole to part.
2. Locate a point by at least two measurements.
1. Work from Whole to Part
- The main idea for working from whole to part is to localize the errors and prevent their accumulation.
- The survey area is covered with the simplest possible frame-work of high quality measurements. If the rest of the survey work is carried out within this area , the possible accumulation of error can be contained.
- If we work from part to whole, the errors accumulate and expand to a greater magnitude in the process of expansion of survey.
2. Locate a Point by at Least Two Measurements
- Two control points A & B (any two important features) are selected in the area and the distance between them is measured accurately. Line AB is called baseline.
- If A & B be the two control points, whose positions are already known on the plan, the position of C can be plotted by any of the following methods.
