Details for Benchmark: JV7254
N 39° 19.929 W 077° 41.340 (NAD 83)
Coordinates may not be exact. Altitude is GPS OBS and location is ADJUSTED. (more info)
- In WASHINGTON county, MD View Original Datasheet
- Marker Type:
- survey disk
- set into the top of a round concrete monument
- May hold, but of type commonly subject to surface motion.
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Documented History (by the NGS)
|01/01/1993 by GREOMA (MONUMENTED)
|DESCRIBED BY GREENHORNE-OMARA 1993
STATION IS LOCATED AT THE INTERSECTION OF MD RTE 340 AND MD RTE 67 WEST OF KNOXVILLE, MD. TO REACH THE STATION TAKE RTE 340 WEST FROM KNOXVILLE AND TAKE THE RTE 67EXIT. STATION IS LOCATED ON THE BRIDGE OVERPASS 23 FEET (7.0 M) SOUTHEAST OF THE CENTERLINE OF RTE 67 AND 115.5 FEET (35.2 M) SOUTHWEST OF THE END OF A GUARDRAIL AT THE SOUTHWEST CORNER OF THE RTE 67 BRIDGE OVER RTE 340. STATION IS A BRASS DISK SET IN THE TOP OF AN 8 INCH ROUND CONCRETE MONUMENT SET FLUSH WITH THE GROUND.
- The horizontal coordinates were established by GPS observations and adjusted by the National Geodetic Survey in February 1994.
- The orthometric height was determined by GPS observations and a high-resolution geoid model.
- 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.