Details for Benchmark: JS0771
N 38° 50.583 W 121° 10.667 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In PLACER county, CA View Original Datasheet
- K 566
- 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)
|01/01/1938 by CGS (MONUMENTED)
|01/01/1947 by NGS (GOOD)
|DESCRIBED BY NATIONAL GEODETIC SURVEY 1947
0.7 MI W FROM PENRYN. NEW DESCRIPTION-- ABOUT 0.7 MILE WEST ALONG THE SOUTHERN PACIFIC CO. RAILROAD FROM THE STATION AT PENYRN, AT A PRIVATE ROAD CROSSING, 45.0 FEET SOUTH OF THE CENTER LINE OF THE PRIVATE ROAD CROSSING, 30.5 FEET WEST OF THE WEST RAIL OF THE MAIN TRACK, SET IN THE TOP OF A CONCRETE POST PROJECTING 0.2 FOOT ABOVE THE GROUND. WITNESS POST SET 1.8 FEET EAST OF THE STATION.
|01/01/1969 by NGS (MARK NOT FOUND)
|RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1969
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. 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.