Details for Benchmark: AC5966
N 47° 28.400 W 087° 51.617 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In KEWEENAW county, MI View Original Datasheet
- 909 9037 OUTCROP
- Marker Type:
- chiseled square
- in rock outcrop
- Most reliable and expected to hold position/elevation well.
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Documented History (by the NGS)
|Unknown by (MONUMENTED)
|07/11/1996 by NGS (GOOD)
|DESCRIBED BY NATIONAL GEODETIC SURVEY 1996 (GAS)
3.0 KM (1.85 MI) EASTERLY ALONG U.S. HIGHWAY 41 FROM THE JUNCTION OF STATE HIGHWAY 26 IN COPPER HARBOR, THENCE 2.1 KM (1.30 MI) NORTHERLY ALONG A GRAVELED ROAD LEADING TO THE COPPER HARBOR LIGHTHOUSE, A CHISELED SQUARE ON THE HIGHEST POINT OF A 15 BY 25-FOOT AREA OF OUTCROPPING BEDROCK, 55.0 M (180.4 FT) SOUTH OF THE SOUTHWEST CORNER OF THE LIGHTHOUSE, 30.0 M (98.4 FT) WEST OF THE SOUTH CORNER OF A ROCK HOUSE, AND 6.5 M (21.3 FT) WEST OF A 24-INCH BIRCH TREE.
- 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 March 1997.
- 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.