Details for Benchmark: BU1397
N 31° 01.467 W 087° 28.233 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In ESCAMBIA county, AL View Original Datasheet
- A 408
- Marker Type:
- bench mark disk
- light structures
- Mark of questionable or unknown stability.
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Documented History (by the NGS)
|01/01/1955 by CGS (MONUMENTED)
|DESCRIBED BY COAST AND GEODETIC SURVEY 1955
1.3 MI E FROM ATMORE. 1.3 MILES EAST ALONG THE LOUISVILLE AND NASHVILLE RAILROAD FROM THE STATION AT ATMORE, ABOUT 0.25 MILE WEST OF MILE POST 620, IN THE TOP AND NEAR CENTER OF THE NORTH HEAD WALL OF A 3-FOOT CONCRETE BOX CULVERT UNDER U.S. HIGHWAY 31, 15 1/2 FEET NORTH OF CENTER LINE OF HIGHWAY, 62 FEET SOUTH OF SOUTH RAIL OF TRACK AND ABOUT 4 1/2 FEET BELOW LEVEL OF TRACK AND ABOUT LEVEL WITH HIGHWAY.
- 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.