Details for Benchmark: AC4647
N 25° 45.711 W 080° 46.154 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is ADJUSTED. (more info)
- In DADE county, FL View Original Datasheet
- FLGPS RON
- Marker Type:
- triangulation station disk
- abutments and piers of large bridges
- Probably hold position/elevation well.
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Documented History (by the NGS)
|1/1/1989 by NGS (MONUMENTED)
|DESCRIBED BY NATIONAL GEODETIC SURVEY 1989
THE STATION IS LOCATED ABOUT 83.02 KM (51.60 MI) WEST OF MIAMI, 37.49 KM (23.30 MI) SOUTHEAST OF MONROE, IN SECTION 18, T 54 S, R 36 E, IN THE SOUTHEAST ABUTMENT OF A BRIDGE OVER A CANAL CONNECTION. OWNERSHIP--HIGHWAY RIGHT-OF-WAY. TO REACH THE STATION FROM THE INTERSECTION OF U.S. HIGHWAY 41 AND STATE ROAD 997 NEAR SWEETWATER, GO WEST FOR 29.44 KM (18.30 MI) ON HIGHWAY 41 TO THE JUNCTION OF SHARK VALLEY ROAD. CONTINUE WEST FOR 0.32 KM (0.20 MI) ON HIGHWAY 41 TO A BRIDGE AND U.S. CORP SPILLWAY AND THE STATION ON LEFT. LOCATED 4.39 M (14.4 FT) SOUTH FROM THE APPROXIMATE CENTER OF HIGHWAY 41, 3.29 M (10.8 FT) NORTH FROM A 5-INCH WATER PIPE WHICH IS ABOVE GROUND AND INTERSECTS WITH HEADWALL, 0.61 M (2.0 FT) WEST FROM A CARSONITE WITNESS POST, 0.21 M (0.7 FT) WEST FROM THE WEST END OF GUARDRAIL ON THE SOUTHEAST SIDE OF BRIDGE AND 0.21 M (0.7 FT) NORTH FROM THE CONCRETE RAIL ON SOUTH SIDE OF BRIDGE. DESCRIBED BY R.L. MALLOY.
|2/19/1992 by NGS (GOOD)
|RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1992
46.8 KM (29.10 MI) WESTERLY ALONG U.S. HIGHWAY 41 FROM THE POST OFFICE IN WEST MIAMI, IN TOP OF AND 0.7 M (2.3 FT) NORTH OF THE SOUTH END OF THE EAST CONCRETE ABUTMENT OF BRIDGE NUMBER 4-20 S-16 SPANNING SPILLWAY NUMBER S-12 B, 4.4 M (14.4 FT) SOUTH OF THE CENTERLINE OF THE HIGHWAY, AND 0.3 M (1.0 FT) ABOVE THE LEVEL OF THE HIGHWAY.
- The horizontal coordinates were established by GPS observations and adjusted by the National Geodetic Survey in September 1990.
- The orthometric height was determined by differential leveling and adjusted by the National Geodetic Survey in September 1992.
- The X, Y, and Z were computed from the position and the ellipsoidal ht.
- The Laplace correction was computed from DEFLEC99 derived deflections.
- The ellipsoidal height was determined by GPS observations and is referenced to NAD 83.
- 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.