Details for Benchmark: SU0212
N 47° 18.867 W 114° 50.950 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In SANDERS county, MT View Original Datasheet
- K 473
- Marker Type:
- bench mark disk
- in rock outcrop
- Most reliable and expected to hold position/elevation well.
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Documented History (by the NGS)
|01/01/1944 by CGS (MONUMENTED)
|DESCRIBED BY COAST AND GEODETIC SURVEY 1944
2.9 MI SW FROM QUINNS. ALONG THE NORTHERN PACIFIC RAILWAY FREIGHT TRACK, 2.9 MILES SOUTHWEST OF THE STATION AT QUINNS, 15 3/4 39-FOOT RAILS NORTHWEST OF SEMAPHORE TOWER NO. 211.5, 11.4 FEET NORTHEAST OF THE NORTHEAST RAIL, ABOUT MIDWAY BETWEEN THE TRACK AND A TELEGRAPH POLE WHICH IS SET IN ROCK LEDGE AND WHICH IS THE 11TH POLE EAST OF MILEPOST NO. 211, 4.0 FEET SOUTHEAST OF THE NORTHWEST BROKEN EDGE OF LAYER OF ROCK STRATA IN WHICH IT IS SET, SET AT BASE OF A DEPRESSION IN SLOPING ROCK STRATA. NOTE-- THIS DEPRESSION SEEMS TO BE CAUSED BY A SOFT, BROWNISH COLORED, EGG SHAPED STONE HAVING BEEN DEPOSITED ALONG WITH THE FINE GRAINED SEDIMENTARY ROCK AND HAVING WEATHERED FASTER THAN THE OTHER PART OF THE FORMATION, ABOUT 2.0 FEET ABOVE THE LEVEL OF THE RAILS.
- 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.