Details for Benchmark: AB0439
N 26° 14.900 W 097° 44.067 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In CAMERON county, TX View Original Datasheet
- O 5 C CO
- Marker Type:
- survey disk
- light structures
- Mark of questionable or unknown stability.
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 (MONUMENTED)
|01/01/1951 by NGS (GOOD)
|DESCRIBED BY NATIONAL GEODETIC SURVEY 1951
IN COMBES. AT COMBES, AT THE INTERSECTION OF U.S. HIGHWAY 77 AND STATE HIGHWAY 107, 34 FEET NORTHEAST OF THE NORTHEAST RAIL OF THE ST. LOUIS, BROWNSVILLE AND MEXICO RAILROAD, 39 FEET SOUTHWEST OF THE CENTER LINE OF U.S. HIGHWAY 77, 50 FEET SOUTH OF THE CENTER LINE OF STATE HIGHWAY 107, SET IN THE TOP OF THE CENTER OF THE SOUTHEAST HEADWALL OF A 12 INCH CONCRETE PIPE CULVERT UNDER STATE HIGHWAY 107.
|01/01/1981 by NGS (GOOD)
|RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1981
IN COMBES, AT THE JUNCTION OF U.S. HIGHWAY 77 AND STATE HIGHWAY 107, 17.3 METERS (57.0 FT) SOUTHEAST OF THE CENTERLINE OF STATE HIGHWAY 107, 13.7 METERS (45.0 FT) SOUTHWEST OF U.S. HIGHWAY 77, 11.8 METERS (39.0 FT) NORTHEAST OF THE NORTHEAST RAIL OF MISSOURI PACIFIC RAILROAD, 1.3 METERS (4.5 FT) SOUTHWEST OF A POWER POLE WITH TRANSFORMER. THE MARK IS 0.6 M BELOW HIGHWAY.
|01/01/1988 by USPSQD (GOOD)
|RECOVERY NOTE BY US POWER SQUADRON 1988 (BJK)
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. WARNING-Repeat measurements at this control monument indicate possible vertical movement.
- 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.