PY0351 "W162 - 1960"
Visited Yellowstone National Park for the first time. A bucket-list item for me. Spent a few hours in West Yellowstone visiting the museum and doing a few tourist things. Looked for a few benchmarks too.
Located in the Town of West Yellowstone, Gallatin County, Montana, this USC&GS mark should lie adjacent to a prominent rock monument for the Union Pacific Railroad. The mark was searched for at 14:20, 23 July 2019. The monument was found, but the mark was not. The description puts the mark in a fairly well manicured grass area. The mark may still be there but I doubt it; it was described as projecting 8 inches (meaning up). I suspect the only part remaining is a portion of the copper-coated steel rod driven to refusal. Go to description is adequate to find the monument.
Published Details for Benchmark: PY0351
N 44° 39.483 W 111° 05.767 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED.
Location: In Gallatin County, MT
Designation: W 162
Marker Type: bench mark disk
Setting: copper-clad steel rod
Stability: Probably hold position/elevation well.
PY0351 "W162 - 1960" - Benchmark location. View southeasterly. PY0351 "W162 - 1960" - Benchmark location. View southeasterly. PY0351 "W162 - 1960" - Benchmark location. View southerly. PY0351 "W162 - 1960" - Benchmark location. View westerly.
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.