Geodetic Database: Minnesota Department of Transportation (Mn/DOT)

The Geodetic Database contains information on permanent geodetic control marks located in Minnesota or just outside its boundaries. Permanent geodetic control marks are established for the purpose of providing precise horizontal and vertical control positions for the registration of surveying and mapping activities in the local area. Information about the location of an object based on its geodetic location locates that object in a worldwide geographic information system. The marks have unique identification and year established stamped on the monument disk, usually an 89 mm (3.5 inch) diameter brass or aluminum disk. Monuments consist of material (concrete or metal) that is meant to stay in place for 50 to 100 years or more, and have little or no movement due to frost action or activity near the monument. The marks have been established by all levels of government in Minnesota, and they are referenced to the National Geodetic Reference System (NAD 1927, NAD 1983, NGVD 1929, and NAVD 1988). The Federal Government supports monumentation at the state level by providing technical expertise, adjustments of the data, and maintenance of the National Geodetic Reference System through its State Advisor Program.