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Details for Benchmark: JU4136

N 39° 20.723 W 075° 38.304 (NAD 83)

Altitude: 51.64

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

Location:
In NEW CASTLE county, DE View Original Datasheet
Designation:
GPS NC 1
Marker Type:
horizontal control disk
Setting:
set into the top of a round concrete monument
Stability:
May hold, but of type commonly subject to surface motion.

Reference Points

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Easy find along Route 13's southbound shoulder.

[Photos:]
photoJU4136
photoJU4136 surrounding area

Found as described.

[Photos:]
photoJU4136

Documented History (by the NGS)

01/01/1990 by DEDHT (MONUMENTED)
01/09/1991 by NGS (GOOD)
DESCRIBED BY NATIONAL GEODETIC SURVEY 1991 STATION IS LOCATED ABOUT 6 KM (3.7 MI) NORTHWEST OF SMYRNA, 0.65 KM (0.40 MI) SOUTHEAST OF BLACK DIAMOND ROAD, ON THE SOUTHBOUND RIGHT-OF-WAY OF US HIGHWAY 13, AT THE EDGE OF A TURF FARM. OWNERSHIP--STATE DEPARTMENT OF TRANSPORTATION. TO REACH FROM THE JUNCTION OF US HIGHWAY 13 AND STATE HIGHWAYS 6 WEST AND 300 IN THE NORTH SECTION OF SMYRNA, GO NORTHWEST ON HIGHWAY 13 FOR 1.92 KM (1.19 MI) TO TO THE ENTRANCE TO A ROADSIDE REST ON THE RIGHT. CONTINUE AHEAD FOR 1.57 KM (0.98 MI) TO SMYRNA LANDING ROAD ON THE RIGHT. CONTINUE AHEAD FOR 1.70 KM (1.06 MI) TO A MEDIAN CROSSOVER ON THE LEFT. TURN LEFT AND RETURN SOUTHBOUND FOR 0.09 KM (0.06 MI) TO THE STATION ON THE RIGHT. STATION MARK IS SET IN THE TOP OF A 30-CM SQUARE CONCRETE POST 1 CM BELOW GOUND. IT IS 92 M (301.8 FT) SOUTHEAST OF THE CENTER OF THE CROSSOVER, 9.5 M (31.2 FT) SOUTHWEST OF, AND 0.4 M (1.3 FT) HIGHER THAN THE CENTER OF THE SOUTHBOUND LANES, 0.4 M (1.3 FT) NORTHWEST OF A FIBERGLASS WITNESS POST, 31.4 M (103.0 FT) SOUTHEAST OF MILEPOST 65, AND 80.8 M (265.1 FT) SOUTHEAST OF TELEPHONE PEDESTAL GB 101. DESCRIBED BY G.R.HEID.

Control Text

  • The horizontal coordinates were established by GPS observations and adjusted by the National Geodetic Survey in October 1991.
  • The orthometric height was determined by differential leveling and adjusted by the National Geodetic Survey in March 1994.
  • The X, Y, and Z were computed from the position and the ellipsoidal ht.
  • The Laplace correction was computed from DEFLEC99 derived deflections.
  • The ellipsoidal height was determined by GPS observations and is referenced to NAD 83.
  • 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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