Details for Benchmark: HT1854
N 37° 49.950 W 122° 13.000 (NAD 83)
Coordinates may not be exact. Altitude is VERTCON and location is SCALED. (more info)
- In ALAMEDA county, CA View Original Datasheet
- L 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
2.1 KM (1.30 MI) SOUTH FROM OAKLAND. 1.3 MILES SOUTH ALONG STATE HIGHWAY 13 FROM THE JUNCTION OF STATE HIGHWAY 24 IN OAKLAND, AT THE MORAGA AVENUE OVERPASS, IN TOP OF THE WEST END OF THE SOUTH CONCRETE ABUTMENT, 19.5 FEET SOUTHWEST OF THE CENTERLINE OF THE SOUTH BOUND LANES OF THE HIGHWAY, 11.4 FEET NORTHWEST OF THE SOUTHEAST END OF A CONCRETE AND METAL GUARD RAIL, 1.7 FEET EAST OF THE WEST END OF THE ABUTMENT 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- The NAVD 88 height was computed by applying the VERTCON shift value to the NGVD 29 height (displayed under SUPERSEDED SURVEY CONTROL.) The vertical order pertains to the superseded datum.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.