As highlighted several times throughout this book, an engineering project can only be implemented with an accurate framework of control points covering the working area. This framework can be local, covering a small area, such as a construction site, or extending over a large region, encompassing an entire country. Generally, for small areas, the control point framework is based on an engineering datum, as described in Sect. , and strategically distributed by the engineer in the working area. It establishes the horizontal reference points and benchmarks for a given construction site. However, for projects in large areas, such as long tunnels, runways, water dams and others, the framework of control points must be based on a Geodetic Datum, as described in Sect. . In these cases, as the number of geodetic control points is not always densified enough to cover the entire project area, the engineer will need to place new ones according to the regulations and standards specified for the project. The planimetric coordinates of the new control points are then determined based on the horizontal geodetic reference system of the country where the project is being implemented.