Work from Whole to Part

System of control points is identified in surveying large areas, and they are located with high precision. Then by using lesser precise methods secondary control points are located. With respect to the secondary control points the details of the localised areas are measured and plotted. This is known working from whole to part. In surveying this principle helps in localising the errors. If by adding localised areas the surveying is carried out errors accumulated and can become unacceptable when large area is covered.