Details for Benchmark: HT1862
N 37° 46.550 W 122° 09.817 (NAD 83)
Coordinates may not be exact. Altitude is VERTCON and location is SCALED. (more info)
- In ALAMEDA county, CA View Original Datasheet
- U 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
1.4 KM (0.90 MI) SOUTH FROM OAKLAND. 0.9 MILES SOUTH ALONG INTERSTATE HIGHWAY 580 FROM THE JUNCTION OF STATE HIGHWAY 13 IN OAKLAND, AT THE EDWARDS AVENUE OVERPASS, IN TOP OF THE SOUTHEAST CONCRETE ABUTMENT, 19.5 FEET SOUTHWEST OF THE WEST CENTERLINE OF THE SOUTH BOUND LANES OF THE HIGHWAY, 10.9 FEET NORTHWEST OF THE EAST CORNER OF THE SOUTHWEST CONCRETE GUARDRAIL, 2.0 FEET NORTHEAST OF THE SOUTHWEST END OF THE ABUTMENT, 1.0 FEET NORTHEAST OF THE SOUTHWEST 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- The NAVD 88 height was computed by applying the VERTCON shift value to the NGVD 29 height (displayed under SUPERSEDED SURVEY CONTROL.) The vertical order pertains to the superseded datum.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.