Details for Benchmark: JC1176
N 38° 41.000 W 090° 11.800 (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
- J 323
- Marker Type:
- metal rod
- stainless steel rod
- Probably hold position/elevation well.
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||happycycler posted a note for JC1176
I did not search for this benchmark. I think that it is on the private side of the floodwall, in the area of a very active grain transfer station (RR, river & truck). I did not bother them or interfere with their progress.
Documented History (by the NGS)
|01/01/1981 by NGS (MONUMENTED)
|DESCRIBED BY NATIONAL GEODETIC SURVEY 1981
IN ST LOUIS. IN ST LOUIS, 1.2 KILOMETERS (0.75 MILE) NORTHWEST ALONG THE FLOOD WALL FROM THE OVERPASS OF THE MERCHANTS BRIDGE, 4.57 METERS (15.0 FEET) NORTHEAST OF THE CENTER OF THE GRAVEL ROAD PARALLEL TO THE FLOOD WALL, 2.2 METERS (7.2 FEET) SOUTHWEST OF THE SOUTHWEST FACE OF THE FLOOD WALL, AND 0.37 METER (1.2 FEET) NORTHWEST OF A METAL WITNESS POST. THE MARK IS 0.37 METERS SE FROM A WITNESS POST. THE MARK IS ABOVE LEVEL WITH ROAD.
- 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.