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Details for Benchmark: HY1087

N 38° 43.517 W 082° 59.867 (NAD 83)

Altitude: 539.33

Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)

Location:
In GREENUP county, KY View Original Datasheet
Designation:
A 354
Marker Type:
bench mark disk
Setting:
massive structures
Stability:
Probably hold position/elevation well.

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Documented History (by the NGS)

01/01/1956 by CGS (MONUMENTED)
01/01/1967 by NGS (GOOD)
DESCRIBED BY NATIONAL GEODETIC SURVEY 1967 0.2 MI SE FROM SOUTH PORTSMOUTH. ABOUT 0.2 MILE SOUTHEAST ALONG THE CHESAPEAKE AND OHIO RAILWAY FROM THE STATION AT SOUTH PORTSMOUTH, SET VERTICALLY IN THE CENTER OF THE EAST FACE OF THE SOUTH CONCRETE PIER OF THE U.S. GRANT BRIDGE (U.S. HIGHWAY 23) OVER THE OHIO RIVER, 66 FEET WEST OF MILEPOST 550, 28.3 FEET SOUTH OF THE SOUTH RAIL OF THE SOUTH TRACK, 3 1/2 FEET ABOVE THE LEVEL OF THE GROUND AND 2 FEET ABOVE THE LEVEL OF THE TRACK.
01/01/1979 by LOCENG (GOOD)
RECOVERY NOTE BY LOCAL ENGINEER (INDIVIDUAL OR FIRM) 1979 RECOVERED IN GOOD CONDITION.

Control Text

  • 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.

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