Details for Benchmark: MJ0212
N 41° 38.667 W 094° 54.267 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In AUDUBON county, IA View Original Datasheet
- Z 99
- 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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Documented History (by the NGS)
|01/01/1935 by CGS (MONUMENTED)
|01/01/1956 by NGS (MARK NOT FOUND)
|DESCRIBED BY NATIONAL GEODETIC SURVEY 1956
1.5 MI S FROM HAMLIN. 1.5 MILES SOUTH ALONG THE CHICAGO, ROCK ISLAND AND PACIFIC RAILROAD FROM THE STATION AT HAMLIN, AUDUBON COUNTY, NEAR POLE 459+20, AT AN EAST-AND-WEST ROAD CROSSING, 33 FEET EAST OF THE CENTERLINE OF THE TRACK, 30 FEET SOUTH OF THE CENTERLINE OF THE ROAD, 7 FEET WEST OF THE RIGHT-OF-WAY FENCE LINE, AND ABOUT 18 INCHES LOWER THAN THE TRACK. A STANDARD DISK, STAMPED Z 99 1935 AND SET IN THE TOP OF A CONCRETE POST. NOTE-- THE ROAD HAS PROBABLY BEEN WIDENED AND THE BENCH MARK WAS DESTROYED.
|01/01/1982 by NGS (MARK NOT FOUND)
|RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1982
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.