The District of Columbia Association of Land Surveyors has formally surveyed the Washington, DC, highpoint at Fort Reno and have declared that it is in a slightly different location than previously believed.
The survey was done at the request of Club Member Robert Hyman. In the pohto above Joe Surveyor Joe Allegra on the left, Robert Hyman and District of Columbia Association of Land Surveyors President, Joe Snider at the DC Highpoint.
The new location is accessible to the general public and is outside of the fenced area where the previous highpoint was.
The coordinates are 38.95198 North and 77.075922 West
The method and description for the initial survey and final survey is as follows.
Utilizing GPS survey techniques, a base station occupied National Geodetic Surveys station Point Identification (PID) AI7414 located on the east side of Military Highway in Rock Creek Park just south of Oregon Avenue. This station was monumented and observed by NGS in 1996 and a brass disk stamped OSENTSO 1996 was set in concrete. The order of the station is listed as “B” or 1 part in 1million in the National Spatial Reference Database at www.ngs.noaa.gov . With the base station established on a High Accuracy Reference Network Station a rover was dispatched to the area designated as the highpoint. This technique allows instant readings at the centimeter level at the survey area. After taking several measurements, the highest part of the area was determined. Two reference stations were established on the ground so the placement of the final monument could easily be established. Utilizing a robotic total station, a topographic survey was completed for the area surrounding the high point.
The final step will be the establishing of the monument and final positioning. Once the monument is poured and the disk is set we will utilize GPS again to collect data on the highpoint and a few surrounding Benchmarks, HARN stations and Continuously Operating Reference Stations (CORS). This data will be submitted to NGS for inclusion in the Database. Once this is completed NGS will then publish the final 3D position for the monument.
Here is the official description proposed:
National Geodetic Survey, Retrieval Date = DECEMBER 16, 2006
DESIGNATION – OSTENSO
STATE/COUNTY- DC/DISTRICT OF COLUMBIA
USGS QUAD – WASHINGTON WEST (1983)
*CURRENT SURVEY CONTROL
* NAD 83(1991)- 38 57 36.44428(N) 077 03 12.39706(W) ADJUSTED
* NAVD 88 – 94.8 (meters) 311. (feet) GPS OBS
X – 1,112,629.111 (meters) COMP
Y – -4,839,918.506 (meters) COMP
Z – 3,988,915.228 (meters) COMP
LAPLACE CORR- -2.92 (seconds) DEFLEC99
ELLIP HEIGHT- 62.86 (meters) (08/09/02) GPS OBS
GEOID HEIGHT- -31.93 (meters) GEOID03
HORZ ORDER – B
ELLP ORDER – THIRD CLASS II
.The horizontal coordinates were established by GPS observations
.and adjusted by the National Geodetic Survey in August 2000..
.The orthometric height was determined by GPS observations and a
.high-resolution geoid model.
.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 GEOID03.
; North East Units Scale Factor Converg.
;UTM 18 – 4,314,356.636 322,080.894 MT 0.99998980 -1 17 29.4
! – Elev Factor x Scale Factor = Combined Factor
!UTM 18 – 0.99999014 x 0.99998980 = 0.99997994
SUPERSEDED SURVEY CONTROL
ELLIP H (08/03/00) 62.85 (m) GP( ) 2 1
.Superseded values are not recommended for survey control.
.NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums.
.See file dsdata.txt to determine how the superseded data were derived.
_U.S. NATIONAL GRID SPATIAL ADDRESS: 18SUJ2208114357(NAD 83)
_MARKER: DH = HORIZONTAL CONTROL DISK
_SETTING: 7 = SET IN TOP OF CONCRETE MONUMENT
_STAMPING: OSTENSO 1996
_MARK LOGO: NGS
_MAGNETIC: N = NO MAGNETIC MATERIAL
_STABILITY: C = MAY HOLD, BUT OF TYPE COMMONLY SUBJECT TO
+STABILITY: SURFACE MOTION
_SATELLITE: THE SITE LOCATION WAS REPORTED AS SUITABLE FOR
+SATELLITE: SATELLITE OBSERVATIONS – March 30, 2000
HISTORY – Date Condition Report By
HISTORY – 1996 MONUMENTED NGS
HISTORY – 20000330 GOOD NGS
‘DESCRIBED BY NATIONAL GEODETIC SURVEY 2000 (RWA)
‘3.95 MI (6.36 KM) WEST ALONG MILITARY BOULVARD FROM THE INTERSECTION
‘OF 16TH STREET NW IN WASHINGTON DC TO THE INTERSECTION OF OREGON AVE.,
‘THENCE 0.1 MI (0.16 KM) SOUTH ALONG OREGON AVE. ENTERING ROCK CREEK
‘PARK TO A PARKING LOT ON RIGHT AND MARK ON THE NORTHWEST CORNER OF A
‘KNOLL, 32.2 METERS (105.8 FT) WEST OF THE CENTERLINE OF OREGON AVE.,
‘24.2 METERS (79.3 FT) NORTHWEST OF A MAPLE TREE, AND 18.6 METERS (61.0
‘FT) NORTH OF NORTH CURB OF PARKING AREA, A CONCRETE POST RECESSED 1 CM
Robert sends along these exact photos:
Here is the view looking north past the Oak tree…
Here is a photo (looking straight down) of the rebar in the ground with a
bit of flagging tape still attached…
Robert passes along these GPS directions:
38 degrees 57 minutes 07N
077 degrees 04 minutes 35W
NAD 27 Lat/Long
Elevation said 125m
Verbal description…the highpoint is 19 paces due north of a large Oak