Ala. Code § 35-2-3

The plane coordinates of a point on the earth’s surface, to be used in expressing the position or location of such point in the appropriate zone of this system, shall consist of two distances, expressed in feet and decimals of a foot. One of these distances, to be known as the “x-coordinate,” shall give the position in an east-and-west direction; the other, to be known as the “y-coordinate,” shall give the position in a north-and-south direction. These coordinates shall be made to depend upon and conform to the coordinates, on the Alabama coordinate system, of the triangulation and traverse stations of the United States coast and geodetic survey within the state of Alabama, as those coordinates have been determined by said survey.