Details for Benchmark: LC1628
N 40° 28.483 W 088° 59.583 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In MCLEAN county, IL View Original Datasheet
- Z 38 RESET
- Marker Type:
- bench mark disk
- abutments and piers of large bridges
- Most reliable and expected to hold position/elevation well.
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Documented History (by the NGS)
|01/01/1981 by ILDT (MONUMENTED)
|DESCRIBED BY ILLINOIS DEPARTMENT OF TRANSPORTATION 1981
IN BLOOMINGTON. IN BLOOMINGTON, IN A CONCRETE LEDGE WITH THE SOUTH ABUTMENT OF THE RAILROAD GRADE SEPARATION STRUCTURE WHICH CARRIES MAIN STREET (U.S. ROUTE 51 NORTHBOUND) OVER THE NOROLK AND WESTERN AND CONRAIL RAILROAD. THE LEDGE IS 1.0 FOOT SQUARE ON THE EAST SIDE OF THE ABUTMENT AT TRACK ELEVATION.
|01/01/1986 by NGS (GOOD)
|RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1986
RECOVERED IN GOOD CONDITION. A NEW DESCRIPTION FOLLOWS. IN BLOOMINGTON, AT THE INTERSECTION OF SOUTH EAST STREET AND THE CONRAIL RAILROAD, IN THE EAST END OF THE SOUTH CONCRETE ABUTMENT OF U.S. HIGHWAY 51 OVERPASS OF THE RAILROAD, 6.0 M (19.7 FT) EAST OF THE CENTERLINE OF THE STREET, 5.1 M (16.7 FT) SOUTHWEST OF THE NEAR RAIL, AND 0.1 M (0.3 FT) WEST OF THE EAST END OF THE ABUTMENT. THE MARK IS 0.6 M ABOVE THE GROUND.
- 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.