Date Added: Jul 2012
Leveling in surveying is the term stand for height difference determination between ground points. If a datum surface is defined for the observed points, the heights of these points (reduced levels) can be computed. In ordinary orthometric leveling Geoid surface is usually used as a datum. Leveling process can be carried out using different survey equipments and techniques. It may be precise; when precise optical or digital levels are used, or it may be ordinary; when using ordinary optical, automatic or digital levels. Moreover it can be carried out trigonometrically or barometrically. Now-a-day Global Positioning System (GPS) provides a quick modern technology to determine heights of points.