Department of Public Works

Survey & GPS Control

Survey Control Documentation

Accurate surveys require survey-grade geodetic control points. Federal, state, and municipal agencies all place, maintain, and document permanent physical control points for public use.

Standards:

• 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.

Resource Links:

• US Survey Foot vs. Meters
• Vertical control
• National Geodetic Survey control
• National Geodetic Survey control point database
• Northampton's GPS Base Station (HAMP CORS)
• Northampton Coordinate System (obsolete)
• Mass DOT survey control