Details for Benchmark: LC0772
N 40° 54.483 W 088° 36.783 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In LIVINGSTON county, IL View Original Datasheet
- LAMBERT AZ MK
- Marker Type:
- azimuth 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)
|01/01/1961 by CGS (MONUMENTED)
|DESCRIBED BY COAST AND GEODETIC SURVEY 1961
2.1 MI NE FROM PONTIAC. ABOUT 2.9 MILES NORTHEAST ALONG U.S. HIGHWAY 66 FROM ITS JUNCTION WITH STATE HIGHWAY 23 IN THE NORTHWEST PART OF PONTIAC, THENCE 0.8 MILES SOUTHWEST ALONG A GRAVEL ROAD, ABOUT 0.35 MILES SOUTHWEST OF THE JUNCTION OF A FARM DRIVE EAST TO A FARM HOUSE, 27 FEET NORTHWEST OF THE CENTER LINE OF THE ROAD, 53 FEET SOUTHEAST OF THE SOUTHEAST RAIL OF THE NORTHBOUND TRACK OF THE GULF, MOBILE AND OHIO RAIL ROAD, 2 FEET SOUTHEAST OF A TELEPHONE POLE, 2.5 FEET SOUTHEAST OF A METAL WITNESS POST, ABOUT LEVEL WITH THE ROAD, AND SET IN THE TOP OF A CONCRETE POST FLUSH WITH 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.