Details for Benchmark: BS0877
N 31° 34.583 W 083° 22.883 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In IRWIN county, GA View Original Datasheet
- B 78
- 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)
|01/01/1934 by CGS (MONUMENTED)
|01/01/1962 by NGS (GOOD)
|DESCRIBED BY NATIONAL GEODETIC SURVEY 1962
5 MI SW FROM MYSTIC. ABOUT 0.45 MILE NORTHWEST ALONG STATE HIGHWAY 32 FROM THE BRICK GRADE SCHOOL AT MYSTIC, THENCE 2.2 MILES SOUTHWEST ALONG A GRADED ROAD, THENCE 0.4 MILE SOUTH ALONG A BLACK TOP ROAD, THENCE 1.15 MILES SOUTHWEST ALONG A GRADED ROAD, THENCE 0.8 MILE SOUTHWEST ALONG THE GRADE OF THE NOW ABANDONED BED OF THE ATLANTIC COAST LINE RAILROAD, 0.4 MILE SOUTHWEST OF MILEPOST 759 WHICH STILL REMAINS, 0.35 MILE SOUTHWEST OF THE REMAINS OF AN OLD RAILROAD BRIDGE, AT A POINT WHERE A DIRT ROAD FORMERLY CROSSED THE RAILROAD TRACK, 26 FEET NORTHWEST OF THE CENTER LINE OF THE RAILROAD BED, 114 FEET WEST OF THE CENTER LINE OF THE ROAD CROSSING THE ABANDONED TRACK, 115 FEET WEST-NORTHWEST OF A FENCE CORNER, 114.5 FEET NORTHEAST OF THE NORTHWEST END OF A 3 FOOT METAL PIPE CULVERT UNDER THE BED, 1.6 FEET NORTHEAST OF A STEEL WITNESS POST, ABOUT LEVEL WITH THE OLD RAILROAD BED, SET IN THE TOP OF A CONCRETE POST 3 INCHES UNDERGROUND.
- 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.