[coordinate systems]
A group of planar coordinate systems based on the division of the United States into more than 130 zones to minimize distortion caused by map projections while defining property boundaries in a way that simplifies calculating land parcel perimeters and areas. Each zone has its own map projection and parameters and uses either the NAD27 or NAD83 horizontal datum. The Lambert conformal conic projection is used for states that extend mostly east–west, while transverse Mercator is used for those that extend mostly north–south. The oblique Mercator projection is used for the panhandle of Alaska.