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Details for Benchmark: NE0630

N 42° 19.217 W 083° 03.883 (NAD 83)

Altitude: 579.37

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

Location:
In WAYNE county, MI View Original Datasheet
Designation:
HL MON 41
Marker Type:
survey disk
Setting:
massive structures
Stability:
Probably hold position/elevation well.

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Documented History (by the NGS)

01/01/1932 by USLS (MONUMENTED)
01/01/1970 by USLS (GOOD)
DESCRIBED BY US LAKE SURVEY 1970 IN DETROIT. HL MON 41 IS IN THE CENTRAL AND SOUTHERN PART OF DETROIT, WAYNE COUNTY MICHIGAN, ON CENTERLINE OF TWELFTH STREET, 2.0 FOOT FROM FACE OF SEA WALL ALONG DETROIT RIVER, BEING HIGHEST POINT AT CENTER OF BRONZE DISC SET INTO THE CONCRETE. NOTE-- PREV. DESIG. BM H L MON 41 1932.
01/01/1980 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1980 RECOVERED IN GOOD CONDITION.
10/30/1993 by LOCENG (GOOD)
RECOVERY NOTE BY LOCAL ENGINEER (INDIVIDUAL OR FIRM) 1993 (KS) RECOVERED AS DESCRIBED.
09/25/1999 by USPSQD (GOOD)
RECOVERY NOTE BY US POWER SQUADRON 1999 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. WARNING-Repeat measurements at this control monument indicate possible vertical movement.
  • 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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