Survey & GPS Control
Survey Control Documentation
Accurate surveys require survey-grade geodetic control points. Federal & state agencies place, maintain, and document control points for public use.
- The current standards for survey datums are Massachusetts Mainland State Plane NAD83 (horizontal) and NAVD88 (vertical)
- Government coordinates are defined in meters
- Converting to and from legacy American units is error-prone since there are different definitions for foot
- Massachusetts chose U.S. Survey Feet as its alternate standard
- National Geodetic Survey (NGS) has free conversion software (NADCON) and detailed information available on their website.