The legislature still has the final say over whether a plan is adopted. Like many midwestern states, Iowa has counties which are mostly four-sided and few large population centers. The LSB's criteria seeks to limit the number of cases in which district lines do not conform with county lines. Crossing counties is occasionally permissible, on the condition that if a city is to be split by a district line, larger cities must be split before smaller ones. Contiguity and compactness are two criteria which address the shape of a district.
Compactness is more difficult to measure.
Two each are chosen by party officials in the legislature, but these four members cannot be partisan office-holders. The fifth member is chosen by a majority vote of the first four. The TRAC holds a minimum of three hearings on the set in different parts of the state. The TRAC then sends the set to the legislature with the recommendation that the plan be either adopted or rejected. Legislators may not amend any of the plans whatsoever.