Details for Benchmark: HU0623
N 38° 24.067 W 075° 42.667 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In WICOMICO county, MD View Original Datasheet
- YY 111
- Marker Type:
- survey disk
- retaining walls, concrete ledge, etc.
- May hold, but of type commonly subject to surface motion.
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Documented History (by the NGS)
|01/01/1968 by MDBCSM (MONUMENTED)
|DESCRIBED BY MD BUR SURV AND MAPS 1968
1.8 MI SW FROM HEBRON. STATION IS AN MBCS DISK STAMPED USC AND GS YY-111-1968 SET FLUSH IN A CONCRETE HEADWALL 19.8 FEET S. OF C/L OF MARYLAND 347, 5.4 FEET N.E. OF E.S.P.S. POLE 27, AND 10.2 FEET W. OF C/L OF DRIVEWAY LEADING TO A 2 STORY FRAME DWELLING. TO REACH FROM R.R. CROSSING IN HEBRON, MARYLAND, GO S.W. ALONG MARYLAND ROUTE 347 FOR 1.75 MILE AND STATION ON LEFT AS DESCRIBED.
|01/24/1990 by NGS (GOOD)
|RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1990
2.8 KM (1.74 MI) SOUTHERLY ALONG STATE HIGHWAY 347 (QUANTICO ROAD)FROM THE POST OFFICE IN HEBRON, IN THE NORTH CORNER OF THE SOUTHWEST CONCRETE HEADWALL OF A CULVERT UNDER A DRIVEWAY, 6.1 M (20.01 FT) SOUTHEAST OF THE CENTERLINE OF THE HIGHWAY, 3.1 M (10.17 FT) SOUTHWEST OF THE CENTER OF THE DRIVEWAY, 1.7 M (5.58 FT) NORTH OF UTILITY POLE NUMBER 43655 94473, AND 0.2 M (0.66 FT) BELOW THE LEVEL OF THE HIGHWAY.
- 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.