Details for Benchmark: MC0258
N 41° 30.717 W 082° 56.783 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In OTTAWA county, OH View Original Datasheet
- P 19
- Marker Type:
- bench mark disk
- massive structures
- Probably hold position/elevation well.
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Documented History (by the NGS)
|01/01/1934 by CGS (MONUMENTED)
|DESCRIBED BY COAST AND GEODETIC SURVEY 1934
AT PORT CLINTON. AT PORT CLINTON, OTTAWA COUNTY, ON THE NEW YORK CENTRAL RAILROAD, 0.4 MILE WEST OF THE STATION, AT THE BRIDGE OVER HARRISON STREET, IN THE NORTH END OF THE WEST BRIDGE SEAT, 14.3 FEET NORTH OF THE NORTH RAIL, AND ABOUT 5 FEET BELOW THE BASE OF THE RAIL. A STANDARD DISK, STAMPED P 19 1934.
|01/01/1980 by NGS (GOOD)
|RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1980
RECOVERED IN GOOD CONDITION.
- 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. WARNING-Repeat measurements at this control monument indicate possible vertical movement.
- 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.