iRedistrict: A Redistricting Software with Human-Computer Collaboration

iRedistrict is a patent-pending redistricting software, with powerful optimization algorithms and intuitive user control. The system leverages the power of user’s judgment, interactive exploration, and computational algorithms to (1) flexibly define various criteria/constraints, (2) efficiently optimize the chosen criteria under constraints, (3) visually and interactively examine alternative plans and achieve a balance among different criteria, and (4) iteratively accumulate a collection of high-quality plans that are difficult to obtain with existing methods. Through such a human-computer collaboration, a user can quickly derive high-quality redistricting plans that satisfy both individual preferences and mandatory requirements, which are difficult to achieve with existing methods.

Population Deviation (PopDev) is the total absolute difference between each district population and its ideal population. For example, PopDev = 200 means that on overage each district's population is within 50 people to the idea population, which is an excellent score for the population equality criterion.

Figure 1: The population for each county in Iowa, from Census 2010. Four congressional districts are needed. (After the 2010 census data, the number of seats was reduced from 5 to 4.)


[30+ more plans...]

Figure 2: Plans generated with iRedistrict with Iowa 2010 census data, considering both population equality and compact shape. The ideal population for each district is 761589. It only took several minutes for the system to find hundreds of such plans, four of which are shown here. It'll be interesting to see what the official plan will be and how it compares with these plans.


Figure 3: Plans generated with iRedistrict with Iowa 2010 census data, considering only population equality. The ideal population for each district is 761589. Although these scores are almost perfect, it is unlikely that the official plan would be one of these.

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  • The methodology and software system is patent-pending.

Here is short demo of an old version of the software.

iRedistrict is hosted at: You can sign up an account and try. 

The materials distributed on this website since 2008 are based upon work partially supported by the National Science Foundation under Grant No. 0748813. Any opinions, findings and conclusions or recomendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).