Illustrated below are the sizes and relationships of idealized townships, ranges, sections and fractional sections. Government townships are designated by their positions relative to east-west latitude lines called base lines and north-south lines of longitude called principal meridians. For example the abbreviation T. 65N., R. 5W., refers to the southernmost township in Lee county in the sixty-fifth tier of townships north of the 1815 Base Line and the fifth township west of a principal meridian. All Iowa townships extend northward from a parallel of latitude passing through central Arkansas and thus have a north designation. The Fifth Principal Meridian enters Iowa in southeastern Muscatine County and leaves the State in central Dubuque County; therefore most Iowa ranges are designated as west, but some are east, depending on their relative position to this meridian. Generally townships are coded along the east and west margins of maps; ranges along the north and south margins.
Government Versus Political Township Specification
An ideal government township is 6 miles long by 6 miles wide and contains 36 sections numbered as shown below, starting with 1 in the northeast corner and ending with 36 in the southeast corner. Each section encompasses an area of 1 square mile or 640 acres. This system of designating land was implemented in Iowa between 1832 and 1859 and is known as the Public Land Survey System (PLSS). This PLSS designation is required by the Iowa UTM Coordinate Generator. Political townships can be of various shapes and sizes and are given proper names such as Beaver Township rather than numerical designations. Government and political townships often encompass the same area, but it should be emphasized that a government township does not necessarily have the same area and boundaries as a political township.
Iowa UTM Coordinate Generator converts a PLSS description of a land area in Iowa and calculates a point centroid location using Universal Traverse Mercator (UTM) coordinates. These UTM coordinates are designated as being Zone 15, NAD27. To use these PLSS descriptions in the application, the quarter sections must be designated from largest (one quarter section) to smallest (one quarter of the preceding area). Thus, quarter section designation is reversed from the form known as the legal description. This allows the program to search logically from large to small.
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