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Details for Benchmark: HW3666

N 38° 39.671 W 078° 19.214 (NAD 83)

Altitude: 2297.8

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

Location:
In RAPPAHANNOCK county, VA View Original Datasheet
Designation:
MARY AZ MK
Marker Type:
azimuth mark disk
Setting:
in a boulder
Stability:
Probably hold position/elevation well.

Reference Points

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Mark found as described. I've seen marks in better condition but it does point right at the top.

Found as expected among three others. Surfaces were difficult to read.

[Photos:]
photoMARY Az, 1965

Found in good condition as described.

Found in good condition.
Report submitted to the NGS.

[Photos:]
photoHW3666 - Closeup
Sorry for the poor photo. It was raining at the time.
photoHW3666 - Area View
Looking Southwest towards Skyline Drive overpass at U.S. Highway 211. Arrow points to station.

First of three benchmarks found in this area today.

Please see the complete recovery, including text and photos, at my website: [b][url=http://surveymarks.planetzhanna.com/reference-marks/hw3666/]HW3666 - MARY AZ MK[/url][/b].

Zhanna

This entry was edited by Zhanna on Saturday, 08 December 2012 at 20:05:18 UTC.

The location is adequately described in the NGS Data Sheet. The large rock outcropping is roughly encircled by the exit ramp from northbound Skyline Drive to US 211. A view of the interchange from near MARY [HW3268] is attached to that log.

[Photos:]
photoMARY AZ MK -- Rappahannock County, VA
photoMARY [HW3268]
Summer view of Marys Rock from MARY AZ MK [HW3666]; US 211 is in the foreground with Skyline Drive crossing on the overpass.

As described.

[Photos:]
photoHW3666 AZ MK.JPG

On a prominent rock in the middle of the exit area.

[Photos:]
photoHW3666- MARY AZ MK mark
photoHW3666- MARY AZ MK site

This azimuth mark disk was found as described.

[Photos:]
photoMARY AZ MK in Rappahannock County, VA
The disk.
photoAt MARY AZ MK in Rappahannock County, VA
Looking across MARY AZ MK toward the East. The sign in view is for Skyline Driva National Park.
photoAt MARY AZ MK in Rappahannock County, VA
From MARY AZ MK looking up toward station MARY on Mary's Rock. The highway in the picture is Skyline Drive and the view is toward the South.

Recovered as described. Fun find.

[Photos:]
photoHW3666

Documented History (by the NGS)

01/01/1965 by CGS (MONUMENTED)
05/18/1992 by NGS (GOOD)
DESCRIBED BY NATIONAL GEODETIC SURVEY 1992 AT SKYLINE DRIVE AT THORNTON GAP,200 FT (61.0 M) NORTH OF US HIGHWAY 211, 180.0 FT (54.9 M) WEST OF ROAD LEADING TO THE SKYLINE DRIVE, 140.0 FT (42.7 M) EAST OF THE NORTHEAST CORNER OF THE BRIDGE OVER U.S. HIGHWAY 211 AND ON THE SKYLINE DRIVE AT THORNTON GAP, IN A LARGE BOULDER THAT PROJECTS 4 FEET (1.2 M).
04/15/1998 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1998 (RWA) FROM THE US211 AND US522 INTERSECTION IN SPERRYVILLE VIRGINIA, GO WEST ON US211 6.9 MI (11.02 KM) TO THE OFF RAMP TO SHENANDOAH NATIONAL PARK ENTRANCE. THE ROCK OUTCROPPING IS ON THE WEST SIDE OF THE ENTRANCE ROAD, IN A CLAER AREA. THE DISK IS SET IN THE LARGEST ROCK OUTCROPPING ON THE HIGHEST PART TOWARDS THE SOUTHWEST END. THE MARK IS A STANDARD NGS AZIMUTH MARK DISK STAMPED MARY AZ MK.
10/02/1998 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1998 (RLA) RECOVERED AS DESCRIBED.
03/01/2000 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 2000 (RWA) RECOVERED AS DESCRIBED.

Control Text

  • The horizontal coordinates were established by GPS observations and adjusted by the National Geodetic Survey in April 1999.
  • The orthometric height was determined by differential leveling and adjusted by the National Geodetic Survey in May 1999.
  • 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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