Details for Benchmark: EH1380
N 34° 17.900 W 091° 20.967 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In ARKANSAS county, AR View Original Datasheet
- U 115
- Marker Type:
- bench mark disk
- light structures
- Mark of questionable or unknown stability.
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Documented History (by the NGS)
|01/01/1954 by CGS (MONUMENTED)
|DESCRIBED BY COAST AND GEODETIC SURVEY 1954
1.0 MI W FROM DEWITT. 1.0 MILE WEST ALONG STATE HIGHWAY 152 FROM THE COURTHOUSE AT DEWITT, 0.45 MILE WEST OF THE HIGH SCHOOL, 18 FEET NORTH OF THE CENTER LINE OF THE HIGHWAY, 20 FEET EAST OF THE EXTENDED CENTER LINE OF A ROAD LEADING SOUTH, SET IN THE TOP OF THE WEST END OF THE NORTH HEADWALL OF A CONCRETE PIPE CULVERT.
|01/01/1976 by NGS (GOOD)
|RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1976
RECOVERED IN GOOD CONDITION.
- 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 August 1993. WARNING-Repeat measurements at this control monument indicate possible vertical movement.
- 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.