70-22-203. Use of x- and y-coordinates. (1) For the Montana coordinate system NAD 27, the plane coordinate values for a point on the earth's surface used to express the geographic position or location of such point in the appropriate zone of this system must consist of two distances expressed in terms of a United States survey foot and decimals of a foot.

(2) For the Montana coordinate system NAD 83 and all later Montana plane coordinate systems, the plane coordinate values for a point on the earth's surface used to express the geographic position or location of such point in the zone must consist of two distances expressed in either meters and decimals of a meter or in feet and decimals of a foot. The international conversion value (1 foot equals 0.3048 meters exactly) must be used. The unit of measure must be clearly stated when the coordinate values are expressed.

(3) One of the distances used to express a position or location, to be known as the "east coordinate" or "x-coordinate", must give the position in an east-and-west direction from the y-axis; the other, to be known as the "north coordinate" or "y-coordinate", must give the position in a north-and-south direction from the x-axis. The y-axis of any zone must be parallel with the central meridian of that zone. The x-axis of any zone must be at a right angle to the central meridian of that zone. These coordinates must be made to depend on and conform to plane rectangular coordinate values derived from the NSRS as defined and promulgated by the national oceanic and atmospheric administration/national geodetic survey or its successors and whose plane coordinates have been computed on the systems designated by this part. Any station with coordinates referenced to the NSRS may be used for establishing a survey connection to the Montana coordinate systems.