Geographic coordinates for STATSGO data

The geographic coordinates used for the 48 conterminous states are in seconds of arc, with west longitude values denoted by negative numbers.

NOTE that geographic coordinates are NOT a projection -- scales vary with latitude and are substantially different in the x and y directions, and the 30-arcsec grid cells are neither square nor equal in area.

The spheroid in terms of which the latitude and longitude are defined has the following characteristics:

        Datum:          NAD27
        Spheroid:       CLARKE1866
	Units:		arcseconds

Relative to this cooordinate system, the polygon version of the dataset has the following bounding coordinates:

        Xmin = -449054 (124°44'14" W)
        Xmax = -241021 (66°57'01" W)
        Ymin =   88365 (24°32'45" N)
        Ymax =  177784 (49°23'04 N)

For the 30-arcsec grid version, the bounding coordinates were extended outwards to an exact multiple of 1 arcminute, giving

        Xmin = -449100 (124°45' W)
        Xmax = -241020 (66°57' W)
        Ymin =   88320 (24°32' N)
        Ymax =  177840 (49°24' N)
        nrow =    2984
        ncol =    6936
        cellsize =  30

For most image processing software packages, the coordinates of the center of the upper left (northwest) cell should be entered as

        x = -449085, y = 177825

Last change: 22 Dec 1995, R. A. White / raw@essc.psu.edu