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Details for Benchmark: OR1045

N 43° 48.367 W 099° 24.700 (NAD 83)

Altitude: 1374.81

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

Location:
In LYMAN county, SD View Original Datasheet
Designation:
I90 259.52
Marker Type:
bench mark disk
Setting:
set into the top of a prefabricated concrete post imbedded in the ground
Stability:
Mark of questionable or unknown stability.

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Found as described and at handheld coordinates N43-48.444 W099-24.709.

[Photos:]
photoOR1045 near Oacoma, SD
Looking southeast, the mark is at the orange hat, at left. Note the pole and I-90 in the background.
photoOR1045 - the Mark

Documented History (by the NGS)

Unknown by SDDT (MONUMENTED)
06/27/1991 by NGS (GOOD)
DESCRIBED BY NATIONAL GEODETIC SURVEY 1991 5.4 KM (3.4 MI) WESTERLY ALONG INTERSTATE HIGHWAY 90 FROM THE WEST END OF THE HIGHWAY BRIDGE SPANNING THE MISSOURI RIVER IN CHAMBERLAIN, ON THE EXTENDED CENTER OF A PAVED ROAD LEADING SOUTH, 91.3 M (299.5 FT) NORTH OF THE CENTERLINE OF THE WESTBOUND LANES OF THE HIGHWAY, 32.2 M (105.6 FT) NORTH OF THE CENTERLINE OF A FRONTAGE ROAD, 11.7 M (38.4 FT) NORTHEAST OF A UTILITY POLE WITH 2 GUY CABLES, 9.7 M (31.8 FT) EAST OF AN UNDERGROUND CABLE JUNCTION BOX, 3.0 M (9.8 FT) BELOW THE LEVEL OF THE FRONTAGE ROAD, 0.3 M (1.0 FT) SOUTH OF A WITNESS POST, AND THE MONUMENT PROJECTS 0.1 M (0.3 FT) ABOVE THE GROUND SURFACE.

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 September 1993.
  • 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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