Meades Ranch Geodetic Center, Kansas

The Meades Ranch geodetic datum point is a small bronze disc in a field, near the center of the country, anchoring a survey point from which nearly a sixth of the world’s surface was geodetically referenced. This was the "Primary Station" for all Mexican, American, and Canadian surveys, known as the North American Datum of 1927 (NAD 27). For most of the modern era, this was the geodetic center of the continent, and one of the most significant survey points in the world. In 1983, the United States Geological Survey adopted a new geodetic reference system based on the Geodetic Reference System 1980 ellipsoid, a geocentric, equipotential reference ellipsoid which incorporated the entire mass of the earth (including the atmosphere). This new geodetic datum was called the North American Datum of 1983 (NAD 83), and its use has resulted in more accurate representations of the Earth’s figure. Thus the origin of the datum was moved from Meades Ranch, to the Earth’s center of mass. There is a historic plaque for the Meades Ranch datum on a nearby highway, but the actual site is on private property, a ranch once owned by the Mead family, 12 miles north of Lucas, Kansas. Until 1983, the significance of the Meades Ranch site to cartographers and surveyors was so tremendous and had such great national and international importance, that were anything to happen to the visible bronze marker, there was another one buried below it.

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