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Details for Benchmark: ME1901

N 41° 53.533 W 087° 38.800 (NAD 83)

Altitude: 613.85

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

Location:
In COOK county, IL View Original Datasheet
Designation:
RV 2
Marker Type:
rivet
Setting:
massive structures
Stability:
Probably hold position/elevation well.

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Documented History (by the NGS)

Unknown by CNWRR (MONUMENTED)
01/01/1947 by NGS (GOOD)
DESCRIBED BY NATIONAL GEODETIC SURVEY 1947 AT CHICAGO. AT CHICAGO, COOK COUNTY, ON THE CHICAGO AND NORTH WESTERN RAILWAY, BETWEEN SIGNAL BRIDGE K AND SIGNAL BRIDGE L, AT THE OHIO STREET SUBWAY, IN THE SOUTHWEST END OF THE NORTHWEST CONCRETE ABUTMENT, 12 FEET NORTH OF THE CENTERLINE OF THE TRACK, AND ABOUT 2 FEET BELOW THE LEVEL OF THE RAIL. A STANDARD MONEL-METAL RIVET.
01/01/1987 by USPSQD (MARK NOT FOUND)
RECOVERY NOTE BY US POWER SQUADRON 1987 (GG) MARK NOT FOUND.

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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