Details for Benchmark: RW0550
N 46° 45.373 W 111° 29.168 (NAD 83)
Coordinates may not be exact. Altitude is VERTCON and location is ADJUSTED. (more info)
- In BROADWATER county, MT View Original Datasheet
- Marker Type:
- survey disk
- in rock outcrop
- Most reliable and expected to hold position/elevation well.
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Documented History (by the NGS)
|1/1/1958 by USGS (MONUMENTED)
|DESCRIBED BY US GEOLOGICAL SURVEY 1958
STATION LOCATED ON THE COUNTY LINE BETWEEN BROADWATER AND MEAGHER COUNTIES, ABOUT 24 MI. E. AND 11 MI. N. OF HELENA, ABOUT 6 MI. S. AND 4 MI. W. OF THE ABANDONED LINKSHIRE POST OFFICE AND ON THE HIGHEST POINT OF AVALANCHE BUTTE.
TO REACH FROM THE JUNCTION OF ANTELOPE CREEK ROAD AND THE MILLEGAN ROAD, PROCEED W. ON ANTELOPE CREEK ROAD ABOUT 5 MI. TO A SIGN --AVALANCHE BUTTE-- AT A RD. JUNCTION. TURN LEFT ON TRAIL RD. 4.2 MI. TO STATION ON HIGHEST POINT OF BUTTE AT SITE OF ABANDONED FOREST SERVICE OBSERVATION POINT.
STATION MARK--STANDARD TABLET CEMENTED IN A DRILL HOLE IN SOLID ROCK AND STAMPED---AVALANCHE 1958---.
REFERENCE MARK NO. 1--CHISELED CROSS ON BEDROCK 7.69 FT. FROM STATION MARK, S 48 DEG 02 MIN W.
REFERENCE MARK NO. 2--DRILL HOLE IN BEDROCK 10.9 FT. FROM STATION MARK, S 23 DEG 12 MIN E.
- The horizontal coordinates were established by classical geodetic methods and adjusted by the National Geodetic Survey in July 1992.
- The NAVD 88 height was computed by applying the VERTCON shift value to the NGVD 29 height (displayed under SUPERSEDED SURVEY CONTROL.)
- The Laplace correction was computed from DEFLEC99 derived deflections.
- The geoid height was determined by GEOID99.