Details for Benchmark: AA7161
N 42° 14.330 W 070° 47.345 (NAD 83)
Coordinates may not be exact. Altitude is VERTCON and location is ADJUSTED. (more info)
- In PLYMOUTH county, MA View Original Datasheet
- Marker Type:
- survey disk
- set into the top of a round concrete monument
- May hold, but of type commonly subject to surface motion.
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Documented History (by the NGS)
|01/01/1994 by NOS (MONUMENTED)
|DESCRIBED BY NATIONAL OCEAN SERVICE 1994 (RPB)
THE STATION IS LOCATED .8 MI (1.3 KM) EAST FROM DOWNTOWN COHASSET, MA IN A SMALL PARK ON GOVERMENT ISLAND. TO REACH THE STATION FROM STATE HIGHWAY 3 AND STATE ROAD 228 HEAD NORTH ON STATE ROAD 228 FOR 6.0 MI (9.7 KM) TO WHERE IT MEETS STATE ROAD 3A, TURN RIGHT ON STATE ROAD 3A AND HEAD EAST FOR 3.0 MI (4.8 KM) TO POND STREET, TURN LEFT ON POND STREET AND HEAD NORTH FOR 0.7 MI (1.1 KM) TO STOP SIGN AT CUSHING STREET, TURN RIGHT ON CUSHING STREET FOR 0.5 MI (0.8 KM) INTO COHASSET VILLAGE AND BEAR RIGHT FOR ANOTHER 0.4 MI (0.6 KM) OVER BRIDGE AND TAKE AN IMMEDIATE LEFT AND PROCEED STRAIGHT AHEAD TO A SMALL PARK. THE STATION IS 78.0 FT (23.8 M) NORTHWEST OF THE NORTHWEST CORNER OF THE SQUARE BASE OF A REPLICA OF THE MINOT''S LEDGE LIGHTHOUSE, 37.0 FT (11.3 M) NORTH OF A LARGE ROCK WITH PLAQUES COMMERATING THE MINOT''S LEDGE LIGHTHOUSE AND 25.0 FT (7.6 M) SOUTH OF A SEAWALL BORDERING COHASSET COVE.
- The horizontal coordinates were established by GPS observations and adjusted by the National Geodetic Survey in June 1998.
- The NAVD 88 height was computed by applying the VERTCON shift value to the NGVD 29 height (displayed under SUPERSEDED SURVEY CONTROL.)
- The X, Y, and Z were computed from the position and the ellipsoidal ht.
- The Laplace correction was computed from DEFLEC99 derived deflections.
- The ellipsoidal height was determined by GPS observations and is referenced to NAD 83.
- The geoid height was determined by GEOID99.