Details for Benchmark: HT1859
N 37° 47.883 W 122° 11.083 (NAD 83)
Coordinates may not be exact. Altitude is VERTCON and location is SCALED. (more info)
- In ALAMEDA county, CA View Original Datasheet
- R 1253
- 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
1.9 KM (1.20 MI) NORTH FROM OAKLAND. 1.2 MILES NORTH ALONG STATE HIGHWAY 13 FROM THE JUNCTION OF INTERSTATE HIGHWAY 580 IN OAKLAND, AT THE REDWOOD ROAD OVERPASS, IN THE TOP OF THE SOUTHWEST CONCRETE ABUTMENT, 15.5 FEET NORTH OF THE CENTERLINE OF THE WEST BOUND LANES OF THE ROAD, 9.4 FEET SOUTHEAST OF THE NORTHWEST END OF THE ABUTMENT, 1.0 FEET NORTH OF THE NORTH CONCRETE GUARDRAIL, AND ABOUT LEVEL WITH THE HIGHWAY.
- 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- The NAVD 88 height was computed by applying the VERTCON shift value to the NGVD 29 height (displayed under SUPERSEDED SURVEY CONTROL.) The vertical order pertains to the superseded datum.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.