Details for Benchmark: CG0021
N 31° 57.983 W 110° 17.383 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In COCHISE county, AZ View Original Datasheet
- W 325
- Marker Type:
- bench mark disk
- massive structures
- Probably hold position/elevation well.
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Documented History (by the NGS)
|1/1/1952 by CGS (MONUMENTED)
|DESCRIBED BY COAST AND GEODETIC SURVEY 1952
IN BENSON. 0.3 MILE EAST ALONG THE SOUTHERN PACIFIC COMPANY RAILROAD FROM THE STATION AT BENSON, IN THE TOP OF THE SOUTH END OF A NORTH-SOUTH RETAINING WALL OF A SOUTHERN PACIFIC COMPANY RAILROAD OVERPASS, AT THE VERTEX OF A NORTH-SOUTH AND AN EASTWEST RETAINING WALL, AND OVER THE CENTER LINE OF STATE HIGHWAY 86, 62 1/2 FEET SOUTH OF MILEPOLE NUMBER 1033, 6.3 FEET NORTHEAST OF THE NORTHEAST RAIL, 0.6 FOOT NORTH OF THE SOUTH END OF A RETAINING WALL, 0.5 FOOT EAST OF THE WEST END OF A WALL, AND 2.9 FEET HIGHER THAN THE TRACK.
|1/1/1960 by NGS (GOOD)
|RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1960
RECOVERED IN GOOD CONDITION.
|1/1/1979 by NGS (GOOD)
|RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1979
AT BENSON, AT THE BENSON RAILROAD OVERPASS BRIDGE OVER BUSINESS ROUTE 10, SET IN TOP OF THE NORTHEAST RETAINING WALL AND IN THE SOUTH END OF THE HEADWALL OVER THE INBOUND LANES, 21.5 FEET NORTHEAST OF THE NORTHEAST RAIL OF THE NORTHEAST TRACKS, 62.5 FEET SOUTHEAST OF RAILROAD MILE POST 1033, 39 FEET WEST OF THE EAST END OF THE HEADWALL IN THE CENTER OF THE BUSINESS ROUTE, AND 27 FEET SOUTH OF THE NORTH END OF THE HEADWALL OVER THE WESTBOUND LANES OF THE BUSINESS ROUTE.
- 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.