Details for Benchmark: HV4109
N 38° 54.430 W 077° 01.201 (NAD 83)
Coordinates may not be exact. Altitude is SCALED and location is ADJUSTED. (more info)
- In DISTRICT OF COLUMBIA county, DC View Original Datasheet
- N W 133-A 1960
- Marker Type:
- triangulation station disk
- setting not listed - see description
- Mark of questionable or unknown stability.
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||two000miler found HV4109
Mark found as described.
OK, with that simple statement made, it is always nice to be the first to log a mark in the city.
Sorry for the approximate distances and lack of photos. I was not planning on going benchmark hunting today. Measurements were made using my size 12 shoes.
Mark is at the SW corner of 6th & N NW. From the corner, go south along 6th St until you come to the first section of the old granite curb (newer stuff is all the same color and has much sharper edges). Mark is about 6 inches from the south end of the first section. Mark is about 25 south of the post for the stoplight, 7 feet south of the smaller electrical box, and about 2 feet SE of the post for the No Parking sign.
3/7/14 - Went back today to take some photos and get a coord reading. I had it at N38 54.409, W 077 01.252.
This entry was edited by two000miler on Saturday, 08 March 2014 at 00:47:54 UTC.
Looking S on 6th St. N St is behind the photographer. Mark is just in front of the white folder and GPSr on the granite curb
Close-up of mark
Documented History (by the NGS)
|01/01/1960 by MADHOP (MONUMENTED)
|DESCRIBED BY MADDOX AND HOPKINS SURVEYORS 1960 (CJM)
STATION IS A STANDARD BRASS DISC STAMPED DISTRICT OF COLUMBIA DEPARTMENT OF HIGHWAYS AND TRAFFIC USC AND GS NO N.W. 133-A GROUTED IN SIDEWALK.
|01/01/1971 by NGS (SEE DESCRIPTION)
|RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1971 (LFS)
STATION HAS BEEN DESTROYED BY CONSTRUCTION OF A NEW CONCRETE SIDEWALK. A SMALL CROSS CHISELED INTO THE SIDEWALK WAS FOUND, INSIDE A SMALL YELLOW CIRCLE, AND A CHECK ON THE DISTANCES FROM THE 3 REFERENCE POINTS INDICATES THAT IT IS AT THE APPROXIMATE LOCATION OF THE OLD STATION.
AIRLINE DISTANCE AND DIRECTION FROM NEAREST TOWN IN DISTRICT OF COL.
- The horizontal coordinates were established by classical geodetic methods and adjusted by the National Geodetic Survey in November 1994.
- The orthometric height was scaled from a topographic map.
- The Laplace correction was computed from DEFLEC99 derived deflections.
- The geoid height was determined by GEOID99.