Details for Benchmark: MG0018
N 41° 30.783 W 090° 24.817 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In ROCK ISLAND county, IL View Original Datasheet
- T 52
- Marker Type:
- bench mark disk
- set into the top of a round concrete monument
- May hold, but of type commonly subject to surface motion.
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Documented History (by the NGS)
|01/01/1934 by CGS (MONUMENTED)
|DESCRIBED BY COAST AND GEODETIC SURVEY 1934
AT SILVIS. AT SILVIS, ROCK ISLAND COUNTY, ON THE CHICAGO, ROCK ISLAND AND PACIFIC RAILWAY, 67 YARDS EAST OF THE STATION, 45 FEET SOUTH OF THE CENTERLINE OF THE SOUTH MAIN TRACK, AND 4 FEET NORTHEAST OF A POLE. A STANDARD DISK, STAMPED T 52 1934 AND SET IN THE TOP OF A CONCRETE POST.
|01/19/1988 by USPSQD (MARK NOT FOUND)
|RECOVERY NOTE BY US POWER SQUADRON 1988 (JEB)
MARK NOT FOUND.
|08/16/1996 by USPSQD (MARK NOT FOUND)
|RECOVERY NOTE BY US POWER SQUADRON 1996
MARK NOT FOUND.
- 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.