North American Datum - North American Datum 1983 and WGS84

North American Datum 1983 and WGS84

The initial definition of NAD83(1986) was intended to match GRS80 and WGS84, and many older publications indicate no difference. Subsequent more accurate measurements found a difference typically on the order of a meter over much of the US. Each datum has undergone refinements with more accurate and later measurements.

One fundamental difference is that NAD83 is defined to remain essentially constant over time for points on the North American Plate, whereas WGS84 is defined with respect to the average of stations all over the world. Thus there is a change over time as to the difference between the systems. For much of the US the relative rate is on the order of 1 to 2 cm per year.

Read more about this topic:  North American Datum

Famous quotes containing the words north american, north, american and/or datum:

    The compulsion to do good is an innate American trait. Only North Americans seem to believe that they always should, may, and actually can choose somebody with whom to share their blessings. Ultimately this attitude leads to bombing people into the acceptance of gifts.
    Ivan Illich (b. 1926)

    The North American system only wants to consider the positive aspects of reality. Men and women are subjected from childhood to an inexorable process of adaptation; certain principles, contained in brief formulas are endlessly repeated by the press, the radio, the churches, and the schools, and by those kindly, sinister beings, the North American mothers and wives. A person imprisoned by these schemes is like a plant in a flowerpot too small for it: he cannot grow or mature.
    Octavio Paz (b. 1914)

    It is as often a weakness in the aged to dictate to the young, as it is folly in the young to slight the warnings of the aged.
    H., U.S. women’s magazine contributor. American Ladies Magazine, pp. 230-3 (May 1828)

    Language fails not because thought fails, but because no verbal symbols can do justice to the fullness and richness of thought. If we are to continue talking about “data” in any other sense than as reflective distinctions, the original datum is always such a qualitative whole.
    John Dewey (1859–1952)