Details for Benchmark: JC0118
N 38° 32.850 W 090° 04.250 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In ST CLAIR county, IL View Original Datasheet
- J 114
- Marker Type:
- bench 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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||Banana80 posted a note for JC0118
For those who have known the area for a while, "Hey Diddle Diddle...." My GPS unit pointed into a steep and wooded ditch at the corner of two main roads. I wasn't going down there by myself, much less in sandals!!!
Documented History (by the NGS)
|01/01/1935 by CGS (MONUMENTED)
|DESCRIBED BY COAST AND GEODETIC SURVEY 1935
2.2 MI SE FROM CENTERVILLE. 2.2 MILES SOUTHEAST ALONG THE ILLINOIS CENTRAL RAILROAD FROM THE CROSSING OF STATE HIGHWAY 157 AT CENTERVILLE, ST. CLAIR COUNTY, AT A HIGHWAY OVERPASS, 13 FEET EAST OF THE CENTERLINE OF THE SOUTHBOUND TRACK, AND ONE FOOT NORTH OF THE FIRST PIER EAST OF THE TRACK. A STANDARD DISK, STAMPED J 114 1935 AND SET IN THE TOP OF A CONCRETE POST PROJECTING 4 INCHES ABOVE 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.