# [EM] Re: Automated districting

Ernest Prabhakar drernie at mac.com
Fri Jan 9 00:11:02 PST 2004

```Thanks for the history lesson, to keep us from reinventing the wheel.
Fascinating, though perhaps not surprising.

> One of these automated districting models uses established political
> units
> (such as municipalities) as districting units and then arranges them
> in the
> districts according to the formula, under which the difference in
> population
> is the smallest possible.

Do you know if it requires contiguity (physical proximity), or does it
pick random cities from around the state to form a given district?

Also, do you happen to have URLs for any of those articles?

Thanks!

-- Ernie P.

On Jan 8, 2004, at 7:58 PM, Toplak Jurij wrote:

> There is no way you can draw rectangles or hexagons or any other shape
> with
> automated districting procedure. Remember, the districts have to have
> equal
> population. You must have some certain units when you draw districts,
> such
> as street blocks or even buildings. Whatever you use, you can never
> draw
> rectangles or hexagons and have equal population in them. Try it and
> you
> will see it easily that it is not possible.
> Several authors have produced automated districting procedures or
> discuss
> these procedures in detail(see the literature below). Many of these
> procedures do work, but none of them is based on certain type of shape
> (such
> as rectangle).
> One of these automated districting models uses established political
> units
> (such as municipalities) as districting units and then arranges them
> in the
> districts according to the formula, under which the difference in
> population
> is the smallest possible.
> Lets say we have 50 municipalities in a state and we have to draw 4
> districts. Matemathically there are many ways we can arrange these 50
> municipalities in 4 districts, but there is only one under which the
> population variance is smallest possible.
> This procedure does not involve decisions of human factor, except for
> the
> decision on the procedure used and political units used. However, the
> decision on which procedure should be used will always be taken by
> humans.
> It could be said that it was humans who drew the borders of the
> municipalities (or other political units used), but these borders have
> usually been drawn long ago and without intent of gerrymandering.
>
> Some literature on automated districting (mostly proposed models):
> The first paper on automated redistricting is Vickrey's short, but
> original
> and often cited 1961 article "On The Prevention Of Gerrymandering"
> (sorry,
> at the moment I dont know exactly where it was published)
> Browdy, Michelle H., Simulated Annealing: An Improved Computer Model
> for
> Political Redistricting, Yale Law & Policy Review 8, 163-179, 1990
> Liittschwager, John M., The Iowa Redistricting System, in Democratic
> Representation and Apportionment: Quantitative Methods, Measures, and
> Criteria, New York: Annals of the New York Academy of Sciences,
> 221-234,
> 1973
> And a case against automated districting:
> Altman, Micah, Is Automation the Answer? The Computational Complexity
> of
> Automated Redistricting, Rutgers Computer and Technology Law Journal
> 23 (1),
> 81-142
>
> Few years ago I wrote, but never published a thesis on a subject of
> automated districting and if someone is interested, let me know.
>
> J.
>
> >    Date: Thu, 08 Jan 2004 09:37:06 +0000
> >    From: "MIKE OSSIPOFF" <nkklrp at hotmail.com>
> > Subject: [EM] Automated districting
> >
> >
> > Hexagons sounds good, till you consider that they won't work at the
> borders
> > of the state being districted. Since district shapes can't be
> hexagons at
> > the state's borders, why bother making hexagons in the interior?
> >
> > The populations or voting populations in the districst of course
> have to
> be
> > exactly equal, or as nearly so as possible.
> >
> > The only important thing about the districts is that they're
> automated and
> > follow from a strictly-applied formula that has no human input, so
> that no
> > one can contrive districts to benefit his/her political party or
> candidates.
> > They needn't be hexagons. They needn't be made by an elaborate
> procedure.
> > Voters will object to an elaborate procedure.  There's no reason not
> to
> use
> > the simplest formula possible. The formula should be as simple as
> possible.
> >
> > The districts should be rectangles (of course the border-districts
> will
> lose
> > some of their rectangularness due to the shape of the border).
> >
> > Of course it's good if there's some effort to make the rectangles
> reasonably
> > nearly square. But any serious effort to achieve that will
> complicate the
> > formula. Don't worry about how square they are.
> > A simple formula can make them reasonably so.
> >
> > When I say "rectangles", I don't mean that the sides must be straight
> lines.
> > Lines of latitude and longitude would make good district borders,
> even
> > though parallels of latitude aren't straight lines on the ground, or
> on
> most
> > maps (but they are on some maps).
> >
> > Straight lines on the ground would be an unnecessarily complicating
> > requirement.
> >
> > Just straight lines on some map. It doesn't matter what map. Lines of
> > latitude & longitude qualify by that requirement. But any kind of
> map will
> > do.
> >
> > In fact, if one wanted to, one could use a map on which a straight
> line on
> > the map is a straight line on the ground. Such a map radicallly
> distorts
> > distances & areas though.
> >
> > Mike Ossipoff
> >

```