Department of Public Works

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.

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