Details for Benchmark: DX3084
N 33° 56.950 W 117° 52.117 (NAD 83)
Coordinates may not be exact. Altitude is READJUSTED and location is SCALED. (more info)
- In LOS ANGELES county, CA View Original Datasheet
- U 348
- Marker Type:
- bench mark disk
- set into the top of a round concrete monument
- May hold, but of type commonly subject to surface motion.
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Documented History (by the NGS)
|01/01/1949 by CGS (MONUMENTED)
|DESCRIBED BY COAST AND GEODETIC SURVEY 1949
3.1 MI NE FROM BREA. ABOUT 2.7 MILES NORTHEAST ALONG THE BREA CANYON ROAD FROM THE GRAMMAR SCHOOL AT THE NORTH EDGE OF BREA AND 0.25 MILES NORTHEAST OF THE LOS ANGELES-ORANGE COUNTY LINE. A 12 INCH SQUARE CONCRETE POST PROJECTING 4 INCHES WHICH IS ON A LOW NARROW RIDGE 5 FEET SOUTHEAST OF RIGHT-OF-WAY FENCE, 45 FEET SOUTHEAST OF HIGHWAY CENTER LINE-- 12 FEET SOUTHEAST OF A WOODEN TRANSMISSION POLE AND 38 FEET SOUTH OF MILE POST 0.23.
|01/01/1970 by LAHSCH (GOOD)
|RECOVERY NOTE BY LOS ALTOS HIGH SCHOOL 1970
RECOVERED IN GOOD CONDITION.
|01/01/1978 by NGS (GOOD)
|RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1978
0.25 MILES NORTHEAST ALONG BREA CANYON ROAD FROM THE LOS ANGELES- ORANGE COUNTY LINE, LOCATED ON A BENCH BETWEEN ROAD AND CREEK, 45 FT. SOUTHEAST THE CENTER LINE BREA CANYON ROAD, 25 FT. EAST OF POWER POLE NUMBER 788930 H, 27 FT. SOUTH OF SOUTHWEST END SOUTHEAST HEAD WALL, 2 FT. SOUTHEAST OF COUNTY WITNESS POST NO PLAQUE.
- 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 February 1993. * This is a READJUSTED BENCH MARK height. Code A indicates a distribution rate of 0.0 thru 1.0 mm/km. The height was derived from older observations constrained to new heights in a crustal motion area. The height is approximate in relation to other heights in its vicinity.
- 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.