Indiana Code Title 32. Property § 32-19-2-1

Sec. 1. (a) The plane coordinates of a point on the earth's surface, used to express the position or location of that point in the appropriate zone of the Indiana coordinate system described in IC 32-19-1, must consist of two (2) distances expressed in:

(b) The distance described in subsection (a) that gives the position in an east-and-west direction is called the “x-coordinate”.  The distance described in subsection (a) that gives the position in a north-and-south direction is called the “y-coordinate”.  These coordinates must be made to depend upon and conform to plane rectangular coordinate values for the monumented points of the North American Horizontal Geodetic Control Network as published by the National Ocean Survey/National Geodetic Survey or its successors, if the successor's plane coordinates have been computed on the Indiana coordinate system of 1927 or the Indiana coordinate system of 1983.  Any station may be used for establishing a survey connection to the Indiana coordinate system of 1927 or the Indiana coordinate system of 1983.