Details for Benchmark: HY1091
N 38° 44.250 W 082° 58.300 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In SCIOTO county, OH View Original Datasheet
- D 208
- Marker Type:
- bench mark disk
- massive structures
- Probably hold position/elevation well.
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Documented History (by the NGS)
|01/01/1958 by CGS (MONUMENTED)
|DESCRIBED BY COAST AND GEODETIC SURVEY 1958
1.6 MI SE FROM PORTSMOUTH. ABOUT 1.6 MILES SOUTHEAST ALONG THE NORFOLK AND WESTERN RAILWAY FROM THE STATION AT PORTSMOUTH, AT THE WEST END OF THE RAILWAY YARDS, SET IN THE TOP OF THE WEST END OF THE CONCRETE BASE OF THE PIER THAT IS BETWEEN THE N. AND W. RY. AND THE BALTIMORE AND OHIO RAILROAD TRACKS AND UNDER THE OLD U.S. HIGHWAY 52 OVERPASS OVER THE TRACKS, 6 FEET NORTH OF NORTH RAIL OF THE NORTH TRACK (N. AND W. RY.), 7 FEET SOUTH OF THE SOUTH RAIL OF THE B. AND O. RR.) TRACK, ABOUT 2 FEET ABOVE THE LEVEL OF THE TRACK.
- 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.