Details for Benchmark: HV1839
N 38° 53.517 W 077° 02.000 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In DISTRICT OF COLUMBIA county, DC View Original Datasheet
- RV VENT
- Marker Type:
- 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 CGS (MONUMENTED)
|01/01/1956 by CGS (GOOD)
|DESCRIBED BY COAST AND GEODETIC SURVEY 1956
AT WASHINGTON. AT WASHINGTON, D.C., NEAR THE SE QUADRANT OF THE INTERSECTION OF CONSTITUTION AVENUE AND 15TH STREET NW, 71 FT S OF THE GATE POST AT THE CORNER, 8.3 FT E OF THE E CURB ALONG 15TH STREET, IN THE SE CORNER OF THE COAMING AROUND A 4-FT SQUARE GRILL.
- 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.