Details for Benchmark: HS4116
N 37° 42.067 W 121° 52.317 (NAD 83)
Coordinates may not be exact. Altitude is VERTCON and location is SCALED. (more info)
- In ALAMEDA county, CA View Original Datasheet
- T 1257
- Marker Type:
- bench mark disk
- abutments and piers of large bridges
- Probably hold position/elevation well.
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Documented History (by the NGS)
|01/01/1974 by NGS (MONUMENTED)
|DESCRIBED BY NATIONAL GEODETIC SURVEY 1974
5.6 KM (3.50 MI) EAST FROM DUBLIN. 3.5 MILES EAST ALONG INTERSTATE HIGHWAY 580 FROM THE JUNCTION OF FOOTHILL ROAD IN DUBLIN, AT THE TASSAJARA ROAD OVERPASS, 24 FEET SOUTH OF THE SOUTH MOST CENTERLINE OF THE EAST BOUND HIGHWAY LANES, SET VERTICALLY IN THE EAST FACE OF THE FIRST CONCRETE SUPPORT PIER SOUTH OF THE EAST BOUND HIGHWAY LANES OF THE OVERPASS, ABOUT 3.5 FEET HIGHER THAN THE GROUND, AND ABOUT 3.5 FEET HIGHER THAN THE HIGHWAY LANES.
- The horizontal coordinates were scaled from a topographic map and have an estimated accuracy of +/- 6 seconds.
- The NAVD 88 height was computed by applying the VERTCON shift value to the NGVD 29 height (displayed under SUPERSEDED SURVEY CONTROL.) The vertical order pertains to the superseded datum.
- The geoid height was determined by GEOID99.