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.