The Northampton Coordinate System (NCS) is an old, local horizontal control datum no longer in use. It is convertible to Mass State Plane (MSP) NAD27 as follows:

NCS Northing + 469,700 = MSP NAD27
NCS Easting + 264,000 = MSP NAD27

MSP NAD27 must then be converted to MSP NAD83 using software like NADCON/CORPSCON, available from National Geodetic Survey.

NAD27 is less accurate than NAD83 and should be avoided whenever possible. Even a careful conversion may produce serious errors since the control itself contains error.

Contact the Engineering Dept. for more information.