Details for Benchmark: BM0439
N 30° 03.133 W 097° 18.200 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In BASTROP county, TX View Original Datasheet
- N 1224
- Marker Type:
- bench mark disk
- copper-clad steel rod
- Probably hold position/elevation well.
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Documented History (by the NGS)
|01/01/1973 by NGS (MONUMENTED)
|DESCRIBED BY NATIONAL GEODETIC SURVEY 1973
4.3 MI SE FROM BASTROP. ABOUT 4.3 MILES SOUTHEAST ALONG THE MISSOURI, KANSAS AND TEXAS RAILROAD FROM THE STATION AT BASTROP, 168.0 FEET SOUTHEAST OF THE CENTER OF A PAVED ROAD CROSSING, 36.6 FEET SOUTHWEST OF THE SOUTHWEST TRACK, 2.4 FEET NORTHWEST OF A TELEPHONE POLE AND IN LINE WITH A ROW OF POLES, 8.2 FEET NORTHEAST OF A FENCE, 0.7 MILES NORTHWEST OF B.M. J 806, 0.5 FEET SOUTHEAST OF A METAL WITNESS POST AND ABOUT 3.0 FEET BELOW THE LEVEL OF THE TRACK AND IS A DISK ON TOP OF A COPPER COATED STEEL ROD PROJECTING 2-IN. PROTECTING A 6-IN IRON PIPE WHICH PROJECTS 5-IN. THE ROD WAS DRIVEN TO A REFUSAL AT A DEPTH OF 29 1/2 FEET.
|01/01/1978 by NGS (GOOD)
|RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1978
RECOVERED IN GOOD CONDITION.
- 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.