Details for Benchmark: LC0685
N 40° 30.183 W 088° 59.017 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In MCLEAN county, IL View Original Datasheet
- N 172
- Marker Type:
- bench mark disk
- light structures
- Mark of questionable or unknown stability.
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Documented History (by the NGS)
|01/01/1954 by CGS (MONUMENTED)
|01/01/1969 by NGS (GOOD)
|DESCRIBED BY NATIONAL GEODETIC SURVEY 1969
0.4 MI S FROM NORMAL. ABOUT 0.45 MILE SOUTH ALONG THE ILLINOIS CENTRAL RAILROAD FROM THE STATION AT NORMAL, OR ABOUT 0.65 MILE EAST ALONG E. WASHINGTON STREET FROM THE MCLEAN COUNTY COURTHOUSE AT BLOOMINGTON, THENCE 1.6 MILES NORTH ALONG THE ILLINOIS CENTRAL RAILROAD, 0.15 MILE NORTH OF A SIDETRACK WHICH LEADS EAST, 0.15 MILE SOUTH OF A CROSSING OF THE RAILROAD AND VERNON STREET, 25 FEET WEST OF THE WEST RAIL, SET IN THE TOP OF THE NORTH END OF THE WEST CONCRETE HEADWALL OF A DOUBLE-CHANNEL CONCRETE CULVERT, AND ABOUT 12 FEET BELOW THE LEVEL OF THE TRACK. SEC 28, T24N, R2E.
- 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.