What is Geodetic Control?
Geodetic control survey points support the production of consistent and spatial accurate data for surveying and mapping. Permanent geodetic monuments provide a consistent coordinate system and serve as the basis for computing lengths and distances between relative positions. To this end, the National Spatial Reference System, managed by the Federal Geodetic Control Subcommittee (FGCS) of the National Geodetic Survey (NGS), is the standard for defining horizontal and vertical position, gravity, and orientation of control points in the United States. Types of Geodetic Control There are two different types of geodetic control: horizontal and vertical. Horizontal control points are typically placed at higher locations to create a clear line of sight and are measured by their position on the earth’s ellipsoid, a mathematical surface used to approximate the shape of the Earth. Vertical control points provide elevations with reference to the geoid, an irregular surface of constant gravitation
