Details for Benchmark: JW1701
N 39° 40.967 W 079° 04.483 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In GARRETT county, MD View Original Datasheet
- SHA 207
- Marker Type:
- survey disk
- abutments and piers of large bridges
- Probably hold position/elevation well.
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Documented History (by the NGS)
|01/01/1992 by MDSHA (MONUMENTED)
|DESCRIBED BY MARYLAND DOT HIGHWAY ADMINISTRATION 1992
THE MARKER IS LOCATED ABOUT 8.0 MI (12.9 KM) WEST-NORTHWEST OF FROSTBURG, 4.4 MI (7.1 KM) EAST-SOUTHEAST OF GRANTSVILLE, AND 2.5 MI (4.0 KM) WEST OF ZION CHURCH. IT IS LOCATED ON INTERSTATE HIGHWAY 68 RIGHT-OF-WAY. TO REACH FROM A POINT WHERE STATE HIGHWAY 546 CROSSES OVER INTERSTATE HIGHWAY 68 AT EXIT NUMBER 29, GO WEST ON INTERSTATE HIGHWAY 68 FOR 5.8 MI (9.3 KM) TO THE MARKER ON THE LEFT. THE POINT IS MARKED WITH A 2.5 INCH MARYLAND STATE HIGHWAY ADMINISTRATION SURVEY DISK, CEMENTED IN A DRILL HOLE IN THE SOUTH END OF A BACKWALL WHICH IS PART OF THE WEST ABUTMENT FOR A BRIDGE NUMBERED 11041 WHERE THE EASTBOUND LANE OF INTERSTATE HIGHWAY 68 WHERE IT CROSSES OVER LOWER NEW GERMANY ROAD. IT IS 2.2 FT (0.7 M) NORTH OF THE NORTH EDGE OF THE MOST SOUTHERLY BRIDGE PARAPET WALL, 12.0 FT (3.7 M) EAST OF THE WEST END OF THE MOST SOUTHERLY BRIDGE PARAPET WALL, 35.0 FT (10.7 M) EAST OF THE CENTER OF A DROP INLET, 19.5 FT (5.9 M) SOUTH FROM THE CENTER OF THE EASTBOUND LANE OF INTERSTATE HIGHWAY 68, AND 0.6 FT (18.3 CM) WEST OF THE MOST WESTERLY BRIDGE EXPANSION JOINT. IT IS ABOUT THE SAME ELEVATION AS THE SURFACE 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 April 1995.
- 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.