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Details for Benchmark: AI4550

N 33° 12.633 W 116° 30.467 (NAD 83)

Altitude: 4131.83

Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)

Location:
In SAN DIEGO county, CA View Original Datasheet
Designation:
SY 64
Marker Type:
survey disk
Setting:
set into the top of a round concrete monument
Stability:
May hold, but of type commonly subject to surface motion.

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Benchmarking day with Mikey. & found KING, HOPE, BAKER, DON, YAP, SY12, SY64, SDPR17, SDPR16, SDPR15, SDPR14, SDPR13, CL25.

Benchmarking day found KING, HOPE, BAKER, DON, YAP, SY12, SY64, SDPR17, SDPR16, SDPR15, SDPR14, SDPR13, CL25

[Photos:]
photoAI4550 Benchmark
N 33° 12.620 W 116° 30.452

Again I used jefj42 coordinates, but if you walk west about 80 feet there is no fence going south (the fence only runs east west along edge of road). I was able to walk right up to disk.
The Fossillady

[This entry was edited by fossillady on Thursday, March 15, 2007 at 2:52:47 PM.]

[This entry was edited by fossillady on Thursday, March 15, 2007 at 2:53:58 PM.]

[Photos:]
photoSY64
N 33° 12.621 W 116° 30.447

130' off of listed coordinates. the old surveyors from the 40's seem to be a lot better than these newbies. YAP is almost right on, but not this one. Didn't get close-up, as this was 8' south of 3 wire fence. (Corrected latitude by subtracting 0.001')

[Photos:]
photoView looking south

Documented History (by the NGS)

01/01/1968 by CA-073 (MONUMENTED)
06/01/1995 by CADT (GOOD)
DESCRIBED BY CALTRANS 1995 (ATD) THE STATION IS LOCATED 0.8 MI (1.3 KM) EAST OF RANCHITA ON THE SOUTH SIDE OF COUNTY ROUTE S-22 AT POST MILE 5.8. TO REACH FROM THE STORE IN RANCHITA DRIVE EAST ON ROUTE S-22 FOR 0.8 MI (1.3 KM) TO INTERSECTION OF TWO DIRT ROADS SOUTH, AND ONE DIRT ROAD NORTH AND THE STATION ON THE SOUTH SIDE OF THE ROAD. THE STATION MARK IS 112 FT (34.1 M) EAST OF THE EASTERN MOST OF THE TWO DIRT ROADS HEADING SOUTH, 133.5 FT (40.7 M) SOUTHEAST OF THE TRIANGULATION STATION YAP, 47.2 FT (14.4 M) SOUTH OF THE CENTERLINE OF S-22, 7.4 FT (2.3 M) SOUTH OF A BARBED WIRE FENCE, LEVEL WITH THE ROAD. THE STATION WAS LEVELED TO BY CADT AS A PART OF THE 1995 PERIPHERAL RUN IN SAN DIEGO COUNTY TO ESTABLISH NAVD 1988.

Control Text

  • 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.

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