Details for Benchmark: AA0296
N 24° 42.350 W 081° 08.283 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In MONROE county, FL View Original Datasheet
- U 278
- Marker Type:
- bench mark disk
- massive structures
- Probably hold position/elevation well.
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Documented History (by the NGS)
|1/1/1966 by CGS (MONUMENTED)
|DESCRIBED BY COAST AND GEODETIC SURVEY 1966
3.8 MI SW FROM MARATHON. ABOUT 3.75 MILES SOUTHWEST ALONG U.S. HIGHWAY 1 FROM THE POST OFFICE AT MARATHON, 0.85 MILE WEST OF THE EAST END OF THE SEVEN MILE BRIDGE, AT MILE POST NO. 46, SET ON THE TOP OF THE NORTH CONCRETE CURB OF THE BRIDGE, 10.0 FOOT NORTH OF THE CENTER LINE OF THE HIGHWAY AND 1/2 FOOT ABOVE THE LEVEL OF THE HIGHWAY.
|1/1/1978 by NGS (GOOD)
|RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1978
RECOVERED IN GOOD CONDITION.
|1/1/1982 by LOCSUR (GOOD)
|RECOVERY NOTE BY LOCAL SURVEYOR (INDIVIDUAL OR FIRM) 1982
ABOUT 3.75 MILES SOUTHWEST ALONG U.S. HWY 1, FROM POST OFFICE AT MARATHON, 0.85 MILES WEST OF THE EAST END OF THE OLD SEVEN MILE BRIDGE, SET IN THE TOP OF THE NORTH CONCRETE CURB, 10.0 FEET NORTH OF CENTERLINE OF HIGHWAY AND 1/2 FOOT ABOVE LEVEL OF 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.