Details for Benchmark: JW1702
N 39° 41.333 W 079° 06.117 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In GARRETT county, MD View Original Datasheet
- SHA 208
- Marker Type:
- survey disk
- mat foundation, concrete slab, etc.
- May hold, but of type commonly subject to surface motion.
Benchmarks may be on private property or in dangerous locations. Obey local laws. By using the services on Geocaching.com you agree to this disclaimer.
Documented History (by the NGS)
|01/01/1992 by MDSHA (MONUMENTED)
|DESCRIBED BY MARYLAND DOT HIGHWAY ADMINISTRATION 1992
THE MARKER IS LOCATED ABOUT 9.5 MI (15.3 KM) WEST-NORTHWEST OF FROSTBURG, 2.9 MI (4.7 KM) EAST OF GRANTSVILLE, AND 3.9 MI (6.3 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 6.85 MI (11.02 KM) TO AN EXIT RAMP FOR EXIT NUMBER 22 THAT LEADS TO CHESTNUT RIDGE ROAD AND U.S. HIGHWAY 219 NORTH. LEAVE INTERSTATE HIGHWAY 68 AND GO WESTERLY ON THE EXIT RAMP FOR 0.45 MI (0.72 KM) TO THE MARKER ON THE RIGHT IN THE CONCRETE BASE FOR A HIGHWAY LIGHT POLE. THE POINT IS MARKED WITH A MARYLAND STATE HIGHWAY ADMINISTRATION SURVEY DISK, CEMENTED IN A DRILL HOLE IN THE SOUTHWEST SIDE OF A 2.5 FT (0.8 M) ROUND CONCRETE BASE FOR A LARGE OVERHEAD HIGHWAY LIGHT POLE NUMBERED 02 18 250. IT IS 22.5 FT (6.9 M) NORTHEAST OF THE CENTER OF THE EXIT RAMP, LEADING TO U.S. HIGHWAY 219 AND CHESTNUT RIDGE ROAD, 26.0 FT (7.9 M) WEST OF THE SOUTHWEST LEG OF A HIGHWAY SIGN POST, AND 38.5 FT (11.7 M) NORTHEAST OF A METAL GUARDRAIL ALONG THE NORTH SIDE OF INTERSTATE HIGHWAY 68. 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.