Skip to Content

Details for Benchmark: JC1164

N 38° 42.100 W 090° 10.883 (NAD 83)

Altitude: 431.54

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

Location:
In MADISON county, IL View Original Datasheet
Designation:
5 LOCK 27 RM
Marker Type:
survey disk
Setting:
massive structures with deep foundations
Stability:
Most reliable and expected to hold position/elevation well.

Must Read!

Benchmarks may be on private property or in dangerous locations. Obey local laws. By using the services on Geocaching.com you agree to this disclaimer.

Documented History (by the NGS)

Unknown by DOD (MONUMENTED)
01/01/1981 by NGS (GOOD)
DESCRIBED BY NATIONAL GEODETIC SURVEY 1981 IN GRANITE CITY. IN GRANITE CITY, AT THE U.S. ARMY CORPS ENGINEERS LOCK NUMBER 27, NEAR THE ENTER OF THE INTERMEDIATE NEAR THE NORTHEAST CORNER OF A CONTROL BUILDING, BETWEEN THE TWO LOCK CHANNELS, 8.23 METERS (27.0 FEET) NORTHEAST OF THE EAST CORNER OF A CONTROL BUILDING, 1.12 METERS (3.7 FEET) NORTHWEST OF THE NORTHWEST EDGE OF THE SOUTHEAST LOCK CHANNEL. THE MARK IS ABOVE LEVEL WITH TOP OF LOCK.

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.

Advertising with Us

Return to the Top of the Page