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Details for Benchmark: HT0027

N 37° 46.217 W 122° 14.233 (NAD 83)

Altitude: 13.02

Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)

Location:
In ALAMEDA county, CA View Original Datasheet
Designation:
T 470
Marker Type:
bench mark disk
Setting:
pavements (street, sidewalk, curb, apron, etc.)
Stability:
Mark of questionable or unknown stability.

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Documented History (by the NGS)

01/01/1951 by CGS (MONUMENTED)
DESCRIBED BY COAST AND GEODETIC SURVEY 1951 AT ALAMEDA. AT ALAMEDA, AT THE INTERSECTION OF PARK STREET AND BLANDING AVENUE, AT THE SOUTHWEST END OF THE PARK STREET BRIDGE OVER THE CHANNEL, IN THE TOP OF THE SOUTHWEST END OF THE CONCRETE BASE OF THE NORTHWEST GUARD RAIL, 23.4 FEET NORTHWEST OF THE CENTER LINE OF PARK STREET, ABOUT 1 FOOT HIGHER THAN THE STREET.
01/01/1963 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1963 RECOVERED IN GOOD CONDITION.
01/01/1984 by USPSQD (GOOD)
RECOVERY NOTE BY US POWER SQUADRON 1984 RECOVERED IN GOOD CONDITION.
01/01/1987 by USPSQD (GOOD)
RECOVERY NOTE BY US POWER SQUADRON 1987 (RAS) RECOVERED IN GOOD CONDITION.
10/11/1988 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1988 RECOVERED IN GOOD CONDITION.

Control Text

  • The horizontal coordinates were scaled from a topographic map and have an estimated accuracy of +/- 6 seconds.
  • The orthometric height was determined by differential leveling and adjusted by the National Geodetic Survey in June 1991.
  • This Tidal Bench Mark is designated as VM 7562 by the Center for Operational Oceanographic Products and Services.
  • The geoid height was determined by GEOID99.
  • The dynamic height is computed by dividing the NAVD 88 geopotential number by the normal gravity value computed on the Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45 degrees latitude (G = 980.6199 gals.).
  • The modeled gravity was interpolated from observed gravity values.

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