Details for Benchmark: QE0491
N 44° 55.450 W 123° 19.450 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In POLK county, OR View Original Datasheet
- DALLAS MAGNETIC STA
- Marker Type:
- bench mark disk
- set into the top of a round concrete monument
- May hold, but of type commonly subject to surface motion.
Benchmarks may be on private property or in dangerous locations. Obey local laws. By using the services on Geocaching.com you agree to this disclaimer.
Documented History (by the NGS)
|01/01/1917 by CGS (MONUMENTED)
|01/01/1973 by USGS (GOOD)
|DESCRIBED BY US GEOLOGICAL SURVEY 1973
IN DALLAS. AT DALLAS IN THE WESTERN PART OF THE CITY PARK 100 FT SE. OF THE SE. END OF A FOOT BRIDGE ACROSS RICKREALL CREEK, 61 FT NNE. OF THE CENTERLINE OF A MAPLE TREE WHOSE IRREGULAR SHAPED BASE IS ABOUT 4 FT IN DIAMETER, 29 FT WSW. OF THE SE. COR. OF A BLOCK RESTROOM BUILDING, 26 FT N. OF THE CENTERLINE OF A PAVED FOOT TRAIL, ON THE E. SIDE AND BENEATH THE FOLIAGE OF A SHRUB ABOUT 5 FT HIGH, A STD. USC AND GS MAGNETIC STATION DISK, STAMPED 320 1917, SET IN THE TOP OF A CONC. POST PROJECTING 0.7 FT.
|09/03/1992 by USPSQD (GOOD)
|RECOVERY NOTE BY US POWER SQUADRON 1992 (RAR)
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. WARNING-Repeat measurements at this control monument indicate possible vertical movement.
- 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.