Details for Benchmark: AI4538
N 33° 06.000 W 116° 27.900 (NAD 83)
Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)
- In SAN DIEGO county, CA View Original Datasheet
- BOR 20
- Marker Type:
- survey 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)
|01/01/1968 by CA-073 (MONUMENTED)
|05/09/1995 by CADT (GOOD)
|DESCRIBED BY CALTRANS 1995 (ATD)
THE STATION IS LOCATED 8.0 MI (12.9 KM) EAST OF JULIAN, NEAR THE JUCTION OF STATE ROUTE 78 AND COUNTY RTE S-2, ON THE SOUTH SIDE OF ROUTE 78 AT POST MILE 70.4. TO REACH FROM THE JUNCTION OF STATE ROUTE 78 AND COUNTY ROUTE S-2, KNOWN LOCALLY AS SCISSORS CROSSING, DRIVE EAST ON 78 FOR 0.7 MI (1.1 KM) TO THE STATION ON THE RIGHT, SOUTH. THE STATION MARK IS 39.5 FT (12.0 M) SOUTH OF CENTERLINE HWY 78, 4 FT (1.2 M) WEST OF A WOOD FENCE POST, 2 FT (0.6 M) SOUTHWEST OF A METAL WITNESS POST, 1.5 FT (0.5 M) NORTH OF A BARBED WIRE FENCE, ABOUT 0.2 FT (6.1 CM) LOWER THAN ROAD. THE STATION WAS LEVELED TO BY CADT AS A PART OF THE 1995 PERIPHERAL RUN IN SAN DIEGO COUNTY TO ESTABLISH NAVD 1988.
- 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 May 2000.
- 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.