Details for Benchmark: AH5799
N 37° 40.667 W 121° 47.400 (NAD 83)
Coordinates may not be exact. Altitude is VERTCON and location is SCALED. (more info)
- In ALAMEDA county, CA View Original Datasheet
- LIVERMORE EAST BASE RM 4
- Marker Type:
- reference 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)
|01/01/1976 by NGS (MONUMENTED)
|01/02/1977 by NGS (GOOD)
|DESCRIBED BY NATIONAL GEODETIC SURVEY 1977
1.1 MILE (1.8 KM) WEST ALONG THE SOUTHERN PACIFIC RAILROAD FROM THE STATION AT LIVERMORE, 6 RAILS WEST OF THE WEST END OF A BRIDGE OVER AROYO MOCHO, ON THE TOP OF A CUT BANK, 89.4 FEET (27.2 M) SOUTH OF TRI STATION LIVERMORE EAST BASE, 45 FEET (13.7 M) NORTH OF THE CENTERLINE OF STANLEY BOULEVARD, 31.0 FEET (9.4 M) SOUTH OF THE SOUTH RAIL OF THE SP CO RR TRACK, 7.8 FEET (2.4 M) WEST OF A TELEPHONE POLE WITH A WITNESS SIGN ATTACHED TO IT, ABOUT 8 FEET (2.4 M) HIGHER THAN THE TRACK, AND SET IN THE TOP OF A CONCRETE POST PROJECTING 0.5 FOOT (15.2 CM) ABOVE THE GROUND.
- 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- The NAVD 88 height was computed by applying the VERTCON shift value to the NGVD 29 height (displayed under SUPERSEDED SURVEY CONTROL.) The vertical order pertains to the superseded datum.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.