Details for Benchmark: MG0088
N 41° 28.833 W 090° 20.950 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In HENRY county, IL View Original Datasheet
- RV 9
- Marker Type:
- massive structures
- Probably hold position/elevation well.
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Documented History (by the NGS)
|Unknown by RIRR (MONUMENTED)
|01/01/1935 by NGS (GOOD)
|DESCRIBED BY NATIONAL GEODETIC SURVEY 1935
AT COLONA. AT COLONA, HENRY COUNTY, ON THE CHICAGO, ROCK ISLAND AND PACIFIC RAILWAY, AT A BRIDGE OVER THE ILLINOIS-MISSISSIPPI CANAL, OPPOSITE CANAL LOCK 28, AND IN THE TOP OF THE SOUTHWEST END OF THE NORTHWEST CONCRETE ABUTMENT. A STANDARD MONEL-METAL RIVET.
|07/17/1996 by USPSQD (GOOD)
|RECOVERY NOTE BY US POWER SQUADRON 1996
RECOVERED IN GOOD CONDITION.
- 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.