Details for Benchmark: AB4811
N 40° 47.510 W 102° 48.135 (NAD 83)
Coordinates may not be exact. Altitude is GPS OBS and location is ADJUSTED. (more info)
- In LOGAN county, CO View Original Datasheet
- JB 55
- Marker Type:
- bench mark 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)
|01/01/1988 by USGS (MONUMENTED)
|01/01/1995 by CODOT (GOOD)
|DESCRIBED BY COLORADO DEPARTMENT OF TRANSPORTATION 1995
STATION IS LOCATED ABOUT 4.5 MILES (7.2 KM) SOUTH OF CROOK, IN STATE RIGHT OF WAY, IN THE NW 1/4 SEC. 2, T. 9 N., R. 49 W. TO REACH FROM EXIT 149 OF I- 76, GO SOUTH ON SH 55 (FROM THE CENTERLINE OF I-76) FOR 2.3 MILES (3.7 KM) TO THE STATION ON THE LEFT (EAST). STATION MARK IS A USGS BRASS CAP IN A CONCRETE MONUMENT, 36 FT (11.0 M) EAST OF SH 55, 44 FT (13.4 M) SOUTH OF A DIRT ROAD LEADING EAST, 15 FT (4.6 M) SOUTH OF A FENCE CORNER AND 3 FT (0.9 M) NORTH OF A FIBERGLASS WITNESS POST (NOAA).
- The horizontal coordinates were established by GPS observations and adjusted by the National Geodetic Survey in July 1996.
- 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.