70-22-205. Technical description of zones. For purposes of more precisely defining the Montana coordinate systems NAD 27 and NAD 83, the following description by the national ocean survey/national geodetic survey (formerly the United States coast and geodetic survey) is adopted:
     (1) The Montana coordinate system NAD 27, north zone, is a Lambert conformal projection of the Clarke spheroid of 1866, having standard parallels at north latitudes 47° 51' and 48° 43', along which parallels the scale shall be exact. The origin of coordinates is at the intersection of the meridian 109° 30' west of Greenwich and the parallel 47° 00' north latitude. This origin is given the coordinates: x = 2,000,000 feet and y = 0 feet.
     (2) The Montana coordinate system NAD 27, central zone, is a Lambert conformal projection of the Clarke spheroid of 1866, having standard parallels at north latitudes 46° 27' and 47° 53', along which parallels the scale shall be exact. The origin of coordinates is at the intersection of the meridian 109° 30' west of Greenwich and the parallel 45° 50' north latitude. This origin is given the coordinates: x = 2,000,000 feet and y = 0 feet.
     (3) The Montana coordinate system NAD 27, south zone, is a Lambert conformal projection of the Clarke spheroid of 1866, having standard parallels at north latitudes 44° 52' and 46° 24', along which parallels the scale shall be exact. The origin of coordinates is at the intersection of the meridian 109° 30' west of Greenwich and the parallel 44° 00' north latitude. This origin is given the coordinates: x = 2,000,000 feet and y = 0 feet.
     (4) The Montana coordinate system NAD 83 is a Lambert conformal conic projection of the GRS 80 (Geodetic Reference System 1980) ellipsoid, having standard parallels of north latitudes 45° 00' and 49° 00', along which parallels the scale shall be exact. The origin of coordinates is at the intersection of the meridian 109° 30' west of Greenwich and the parallel 44° 15' north latitude. This origin is given the coordinates: x = 600,000 meters and y = 0 meters.

     History: En. Sec. 5, Ch. 232, L. 1965; amd. Sec. 2, Ch. 73, L. 1975; R.C.M. 1947, 67-2015; amd. Sec. 5, Ch. 137, L. 1987.