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Details for Benchmark: ME1856

N 41° 41.233 W 087° 54.933 (NAD 83)

Altitude: 619.91

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

Location:
In COOK county, IL View Original Datasheet
Designation:
J 137
Marker Type:
bench mark disk
Setting:
light structures
Stability:
Mark of questionable or unknown stability.

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Found the mark in good condition.

[This entry was edited by Team Fawlty on Wednesday, June 24, 2009 at 10:24:13 AM.]

[Photos:]
photoME1856
photoSetting

Finally found this one using Fawlty's coords. Will post pics soon.

[Photos:]
photoME1856 setting
photoME1856

The scaled coords .1 mile off. New coords: N 41 41.238 W 087 55.005

[Photos:]
photoJ 137
photoME1856a.jpg
photoME1856b.jpg
photoME1856c.jpg

It appeared as though the wall had deteriorated along with the mark. A pic will follow

[Photos:]
photoCacheJan02 009.jpg
The area

Documented History (by the NGS)

01/01/1947 by CGS (MONUMENTED)
DESCRIBED BY COAST AND GEODETIC SURVEY 1947 13.1 MI NW FROM BLUE ISLAND. ABOUT 13.1 MILES NORTHWEST ALONG STATE HIGHWAY 83 FROM THE GRAND TRUNK AND WESTERN RAILROAD STATION AT BLUE ISLAND, ABOUT 1.25 MILE SOUTHEAST OF THE BRIDGE OVER CALUMET SAG, ABOUT 0.9 MILE EAST OF THE INTERSECTION OF ARCHER AVENUE, SET IN THE TOP OF THE CENTER OF THE SOUTH HEAD WALL OF A 3-FOOT CONCRETE BOX CULVERT UNDER THE HIGHWAY, DIRECTLY ACROSS THE HIGHWAY FROM A LIMESTONE ROCK BED, 31 FEET SOUTH OF AND ABOUT 0.5 FOOT BELOW THE CENTER LINE OF THE HIGHWAY.
01/01/1971 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1971 RECOVERED IN GOOD CONDITION.
01/01/1977 by NGS (GOOD)
RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1977 RECOVERED IN GOOD CONDITION.

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 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.

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