Details for Benchmark: EF1340
N 34° 38.700 W 087° 08.950 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In LAWRENCE county, AL View Original Datasheet
- MCT 1 TVA
- Marker Type:
- survey 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)
|01/01/1938 by TVA (MONUMENTED)
|01/01/1982 by NGS (GOOD)
|DESCRIBED BY NATIONAL GEODETIC SURVEY 1982
18.1 KM (11.2 MI) WEST FROM DECATUR. 0.65 KM (0.4 MI) NORTH ALONG WELL STREET NORTHEAST FROM THE POST OFFICE IN DECATUR, THENCE 17.3 KM (10.75 MI) WEST ALONG U.S. HIGHWAY 72 ALTERNATE, THENCE 0.08 KM (0.05 MI) NORTH ALONG A GRAVEL ROAD, AT THE JUNCTION WITH AN ASPHALT ROAD WHICH IS PARALLEL TO HIGHWAY 72 ALTERNATE, 11.4 METERS (37.5 FT) SOUTHWEST OF APPROXIMATE CENTER OF ASPHALT ROAD, 54.9 METERS (180.0 FT) SOUTHEAST OF A GRAVEL ROAD, 2.4 METERS (8.0 FT) SOUTH OF THE WEST END OF A 31 CENTIMETER (12 INCH) PIPE CULVERT, 15.9 METERS (52.0 FT) EAST OF A PRIVATE DRIVE, 6.3 METERS (20.8 FT) SOUTHEAST OF THE CENTER OF A CONCRETE HEADWALL OF A 31 CENTIMETER (12 INCH) CULVERT, AND 40.2 METERS (132.0 FT) EAST OF A POWERLINE POLE. NOTE, HIGH POINT HELD. THE MARK IS 0.3 METERS N FROM A WITNESS POST. THE MARK IS ABOVE 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.