TT0721 "945 5920 TIDAL 12 1947"

We were able to visit family in Anchorage, Alaska during the first week of July, spending 04 July sightseeing around town.  Spent some time to find a few benchmarks too.

Located in the City of Anchorage, Anchorage Borough, Alaska, this USC&GS mark lies in one of the doorways to the Alaska Railroad Train Station. The USC&GS mark stamped "No 12 1947" was found - with the help of a Station employee who knew just where it was - at 15:15, 04 July 2007 as described and in generally good condition. Go to description is adequate to find the mark.

No new coordinates were taken.

View Original Datasheet Here

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Published Details for Benchmark: TT0721

N 61° 13.283, W 149° 53.267 (NAD 83)

Altitude: 28.89

Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED.

Location: In Anchorage Borough, AK

Designation: 945 5920 TIDAL 12

Marker Type: bench mark disk

Setting: light structures

Stability: Mark of questionable or unknown stability.

TT0721 "945 5920 TIDAL 12 1947" - Benchmark detail.

TT0721 "945 5920 TIDAL 12 1947" - Benchmark setting in the Train Station doorway.

TT0721 "945 5920 TIDAL 12 1947" - Junior benchmark hunters locate the mark.

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Documented History (by the NGS)

01/01/1947 by CGS (MONUMENTED)

01/01/1975 by NGS (GOOD)

DESCRIBED BY NATIONAL GEODETIC SURVEY 1975 IN ANCHORAGE. AT ANCHORAGE, 0.1 MILE WEST ALONG WEST 1ST AVENUE FROM THE JUNCTION OF C STREET, AT THE NORTH ENTRANCE TO THE ALASKA RAILROAD STATION, IN THE TOP OF THE WEST END OF THE CONCRETE DOORWAY TO THE TICKET OFFICE, 112.0 FEET WEST OF THE NORTHEAST CORNER OF THE STATION BUILDING, 37.0 FEET WEST OF BENCH MARK TIDAL 1 (ARR), 47.9 FEET SOUTH OF THE SOUTH RAIL OF THE MAIN TRACK, AND ABOUT LEVEL WITH THE ASPHALT SURFACE OF A WALKWAY. SEC 18, T 13N, R 3W.

Control Text

• 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.