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Details for Benchmark: OQ1094

N 43° 36.567 W 096° 29.583 (NAD 83)

Altitude: 1438.09

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

Location:
In MINNEHAHA county, SD View Original Datasheet
Designation:
I90 410.5
Marker Type:
NGS Benchmark
Setting:
setting not listed - see description
Stability:
Most reliable and expected to hold position/elevation well.

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Documented History (by the NGS)

01/01/1990 by SDDT (MONUMENTED)
05/26/1991 by NGS (GOOD)
DESCRIBED BY NATIONAL GEODETIC SURVEY 1991 16.0 KM (9.9 MI) EASTERLY ALONG INTERSTATE HIGHWAY 90 FROM THE JUNCTION OF INTERSTATE HIGHWAY 229 AT THE NORTHEAST EDGE OF SIOUX FALLS, A STAINLESS STEEL BALL EPOXIED TO A PIPE CAP THAT IS ATTACHED TO A 1 1/2-INCH GALVANIZED STEEL PIPE, 108.3 M (355.3 FT) NORTHWEST OF THE NORTHWEST CORNER OF OVERPASS NUMBER 50-320-166 (EXIT 410), 99.6 M (326.8 FT) WEST OF THE CENTERLINE OF COUNTY ROAD 105, 79.3 M (260.2 FT) NORTH OF THE CENTERLINE OF THE WESTBOUND LANES OF THE HIGHWAY, 29.4 M (96.5 FT) NORTHWEST OF THE CENTER OF THE WESTBOUND ON RAMP, 18.8 M (61.7 FT) WEST OF THE MOST WESTERLY OF 2 BRACED FENCE POSTS, 4.0 M (13.1 FT) BELOW THE LEVEL OF THE RAMP, 0.7 M (2.3 FT) SOUTH OF THE FENCE, AND 0.4 M (1.3 FT) SOUTH OF A WITNESS POST. NOTE--ACCESS TO THE DATUM POINT IS THROUGH A 5-INCH LOGO CAP AND THEN THROUGH A 4-INCH PVC SCREW CAP.

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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