Details for Benchmark: LX2812
N 41° 31.033 W 072° 40.067 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In MIDDLESEX county, CT 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)
|01/01/1940 by CTGS (MONUMENTED)
|01/01/1985 by NGS (GOOD)
|DESCRIBED BY NATIONAL GEODETIC SURVEY 1985
5.1 KM (3.2 MI) SOUTH FROM MIDDLETOWN. 3.6 KM (2.25 MI) WEST ALONG STATE HIGHWAY 155 FROM THE OVERPASS OF STATE HIGHWAY 9 IN MIDDLETOWN, THENCE 1.5 KM (0.95 MI) SOUTH ALONG STATE HIGHWAY 17 TO THE MARK ON THE RIGHT, DIRECTLY UNDER A METAL GUARD RAIL, 6.10 METERS (20.0 FT) WEST OF THE CENTERLINE OF THE HIGHWAY, 7.65 METERS (25.1 FT) NORTHWEST OF UTILITY POLE 3392, 0.61 METER (2.0 FT) NORTH OF THE SOUTH END OF THE GUARD RAIL. THE MARK IS 0.1 M BELOW HIGHWAY.
- The horizontal coordinates were scaled from a topographic map and have an estimated accuracy of +/- 6 seconds.
- The orthometric height was determined by differential leveling and adjusted by the National Geodetic Survey in June 1991.
- The geoid height was determined by GEOID99.
- The dynamic height is computed by dividing the NAVD 88 geopotential number by the normal gravity value computed on the Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45 degrees latitude (g = 980.6199 gals.).
- The modeled gravity was interpolated from observed gravity values.