Details for Benchmark: JC1177
N 38° 41.667 W 090° 12.533 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In C OF ST LOUIS county, MO View Original Datasheet
- H 323
- Marker Type:
- metal rod
- stainless steel rod
- Probably hold position/elevation well.
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Documented History (by the NGS)
|01/01/1981 by NGS (MONUMENTED)
|DESCRIBED BY NATIONAL GEODETIC SURVEY 1981
IN ST LOUIS. IN ST LOUIS, 4.25 KILOMETERS (2.65 MILES) SOUTH ALONG THE MISSISSIPPI RIVER LEVEE FROM THE JUNCTION OF THE BURLINGTON NORTHERN OVERPASS BRIDGE AND RIVERVIEW DRIVE IN THE NORTHEAST SECTION OF ST LOUIS TO THE END OF THE LEVEE AND THE START OF A CONCRETE RETAINING WALL, 55.78 METERS (183.0 FEET) SOUTHEAST OF THE CENTER OF A Y JUNCTION ON TOP OF THE LEVEE, 13.11 METERS (43.0 FEET) NORTHWEST OF THE NORTHWEST EXPOSED END OF THE CONCRETE RETAINING WALL, AND 0.32 METER (1.1 FEET) NORTHWEST OF A METAL WITNESS POST. THE MARK IS 0.32 METERS SE FROM A WITNESS POST. THE MARK IS ABOVE LEVEL WITH LEVEE.
|03/26/1991 by USPSQD (MARK NOT FOUND)
|RECOVERY NOTE BY US POWER SQUADRON 1991 (DWS)
MARK NOT FOUND.
- 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.