Details for Benchmark: RL0621
N 46° 45.567 W 088° 45.683 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In HOUGHTON county, MI View Original Datasheet
- J 152
- Marker Type:
- bench mark disk
- light structures
- Mark of questionable or unknown stability.
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Documented History (by the NGS)
|01/01/1948 by CGS (MONUMENTED)
|DESCRIBED BY COAST AND GEODETIC SURVEY 1948
0.4 MI S FROM ALSTON. 0.05 MILE WEST ALONG STATE HIGHWAY 35 FROM THE SCHOOL AT ALSTON, THENCE ABOUT 0.35 MILE SOUTH ALONG A GRAVEL ROAD, SET IN THE TOP OF THE NORTH END OF THE WEST HEAD WALL OF A 4-FOOT CONCRETE CULVERT, 35 FEET WEST OF THE CENTER LINE OF THE ROAD, 1/2 FOOT SOUTH OF THE NORTH END OF HEAD WALL AND ABOUT 3 FEET BELOW THE ROAD.
- 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.
- 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.