Details for Benchmark: HS4004
N 37° 42.117 W 121° 53.250 (NAD 83)
Coordinates may not be exact. Altitude is VERTCON and location is SCALED. (more info)
- In ALAMEDA county, CA View Original Datasheet
- P 20
- Marker Type:
- bench 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)
|01/01/1964 by CGS (MONUMENTED)
|DESCRIBED BY COAST AND GEODETIC SURVEY 1964
4.2 MI NW FROM PLEASANTON. 0.95 MILES NORTHWEST ALONG DIVISION STREET FROM THE WESTERN PACIFIC RAILROAD STATION AT PLEASANTON, THENCE 2.45 MILES NORHTWEST ALONG HOPYARD ROAD, THENCE 0.85 MILES EAST ALONG U.S. HIGHWAY 50, 157 FEET WEST OF THE CENTER LINE OF AN ABANDONED DRIVEWAY LEADING NORTH TO CAMP PARKS, 61 FEET NORTH OF THE CENTER LINE OF THE NORTH HIGHWAY LANES, 1.1 FEET NORTH OF A WITNESS POST, 1.0 FOOT SOUTH OF A FENCE, ABOUT 1 FOOT LOWER THAN THE HIGHWAY, A DISK ON THE TOP OF A COPPER COATED ROD DRIVEN TO A DEPTH OF 104 FEET. THE UPPER PORTION OF THE ROD IS ENCASED IN A CONCRETE POST FLUSH WITH THE GROUND.
|01/01/1968 by NGS (GOOD)
|RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1968
RECOVERED IN GOOD CONDITION.
- 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- The NAVD 88 height was computed by applying the VERTCON shift value to the NGVD 29 height (displayed under SUPERSEDED SURVEY CONTROL.) The vertical order pertains to the superseded datum.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.