Details for Benchmark: TT0808
N 61° 00.067 W 149° 39.183 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In county, AK View Original Datasheet
- R 11
- Marker Type:
- bench mark disk
- in rock outcrop
- Most reliable and expected to hold position/elevation well.
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Documented History (by the NGS)
|01/01/1923 by CGS (MONUMENTED)
|01/01/1975 by NGS (GOOD)
|DESCRIBED BY NATIONAL GEODETIC SURVEY 1975
21.2 MI S FROM ANCHORAGE. 9.3 MILES SOUTH ALONG THE ALASKA RAILROAD FROM THE STATION AT ANCHORAGE, THENCE 0.1 MILE EAST ALONG OREGON STREET, THENCE 4.7 MILES SOUTHEAST ALONG OLD SEWARD HIGHWAY, THENCE 7.1 MILES SOUTHEAST ALONG STATE HIGHWAY 1, ABOUT 0.15 MILE EAST OF ALASKA RAILROAD MILEPOST 94, 95 YARDS SOUTHEAST OF THE CENTER LINE OF A ROAD TO A GRAVEL PIT, 22 1/2 FEET NORTHEAST OF THE CENTER LINE OF THE HIGHWAY, SET VERTICALLY IN THE SOUTHWEST FACE OF AN OUTCROP, 112 FEET NORTH OF AND ACROSS THE HIGHWAY FROM THE NORTHWEST END OF A STEEL GUARDRAIL, 32 FEET SOUTHEAST OF THE CENTER OF THE NORTHEAST END OF A 24-INCH PIPE CULVERT, ABOUT 4 FEET HIGHER THAN THE GROUND AND ABOUT 5 1/2 FEET HIGHER THAN THE HIGHWAY. SEC 33, T 11N, R 2W.
- 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.