Details for Benchmark: AL6487
N 28° 01.950 W 082° 26.550 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In HILLSBOROUGH county, FL View Original Datasheet
- C 40
- Marker Type:
- bench mark disk
- set into the top of a round concrete monument
- May hold, but of type commonly subject to surface motion.
Benchmarks may be on private property or in dangerous locations. Obey local laws. By using the services on Geocaching.com you agree to this disclaimer.
Documented History (by the NGS)
|Unknown by CGS (MONUMENTED)
|01/01/1933 by NGS (GOOD)
|DESCRIBED BY NATIONAL GEODETIC SURVEY 1933
IN SULPHUR SPRINGS. IN TOWN. LOCATED ALONG THE SEABOARD AIR LINE RAILWAY RIGHT OF WAY. 200 YARDS NORTH OF SULPHUR SPRINGS STATION. 28.7 FT. WEST OF CENTER LINE OF TRACK. 37.6 FT. NORTHWEST OF POINT OF SWITCH. 20.7 FT NORTH OF TELEGRAPH POLE. 47.4 FT. NORTHEAST OF CENTER LINE OF ASPHALT BLOCK PAVED ROAD.
|03/19/1991 by USPSQD (GOOD)
|RECOVERY NOTE BY US POWER SQUADRON 1991 (RF)
RECOVERED IN GOOD CONDITION.
- 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.