Details for Benchmark: LC0762
N 40° 50.650 W 088° 39.533 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In LIVINGSTON county, IL View Original Datasheet
- T 248
- Marker Type:
- bench mark disk
- massive structures
- Probably hold position/elevation well.
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)
|01/01/1961 by CGS (MONUMENTED)
|DESCRIBED BY COAST AND GEODETIC SURVEY 1961
2.3 MI SW FROM PONTIAC. ABOUT 2.3 MILES SOUTHWEST ALONG U.S. HIGHWAY 66 FROM ITS JUNCTION WITH STATE HIGHWAY 116 IN THE SOUTHWEST PART OF PONTIAC, AT THE JUNCTION OF AN EAST-WEST GRAVEL ROAD, SET IN THE TOP OF THE NORTHWEST END OF A CONCRETE BRIDGE SEAT AT THE NORTHEAST END OF A 12 FOOT TRESTLE UNDER THE GULF, MOBILE AND OHIO RAIL ROAD, 7.5 FEET NORTHWEST OF THE NORTHWEST RAIL OF THE SOUTHBOUND TRACK OF THE GULF, MOBILE AND OHIO RAIL ROAD, 90 FEET SOUTHEAST OF THE CENTER LINE OF THE NORTHBOUND LANE OF U.S. HIGHWAY 66, 102 FEET SOUTHWEST OF THE CENTER OF THE CROSSING OF THE SOUTHBOUND TRACK AND THE GRAVEL ROAD EAST, 3.5 FEET BELOW THE LEVEL OF THE TRACK, AND ABOUT LEVEL WITH THE HIGHWAY.
- 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.