Editing Gerrymandering (section)

====Shortest splitline algorithm====
The [[Center for Range Voting]] has proposed<ref>{{cite web|url=http://www.RangeVoting.org/GerryExamples.html|title=Gerrymandering and a cure—shortest splitline algorithm|publisher=RangeVoting.org|access-date=5 August 2009}}</ref> a way to draw districts by a simple [[algorithm]].<ref>{{Cite web|url=https://www.rangevoting.org/|title=RangeVoting.org – Center for Range Voting – front page|website=www.rangevoting.org}}</ref> The algorithm uses only the shape of the state, the number {{var|N}} of districts wanted, and the population distribution as inputs. The algorithm (slightly simplified) is:

# Start with the boundary outline of the state.
# Let {{var|N}}=A+B where {{var|N}} is the number of districts to create, and A and B are two whole numbers, either equal (if {{var|N}} is even) or differing by exactly one (if {{var|N}} is odd). For example, if {{var|N}} is 10, each of {{var|A}} and {{var|B}} would be 5. If {{var|N}} is 7, {{var|A}} would be 4 and {{var|B}} would be 3.
# Among all possible straight lines that split the state into two parts with the population ratio A:B, choose the ''shortest''. If there are two or more such shortest lines, choose the one that is most north–south in direction; if there is still more than one possibility, choose the westernmost.
# We now have two hemi-states, each to contain a specified number (namely {{var|A}} and {{var|B}}) of districts. Handle them recursively via the same splitting procedure.
# Any human residence that is split in two or more parts by the resulting lines is considered to be a part of the most north-eastern of the resulting districts; if this does not decide it, then of the most northern.

This district-drawing algorithm has the advantages of simplicity, ultra-low cost, a single possible result (thus no possibility of human interference), lack of intentional bias, and it produces simple boundaries that do not meander needlessly. It has the disadvantage of ignoring geographic features such as rivers, cliffs, and highways and cultural features such as tribal boundaries. This landscape oversight causes it to produce districts different from those a human would produce. Ignoring geographic features can induce very simple boundaries.

While most districts produced by the method will be fairly compact and either roughly rectangular or triangular, some of the resulting districts can still be long and narrow strips (or triangles) of land.

Like most automatic redistricting rules, the shortest splitline algorithm will fail to create majority-minority districts, for both ethnic and political minorities, if the minority populations are not very compact. This might reduce minority representation.

Another criticism of the system is that splitline districts sometimes divide and diffuse the voters in a large metropolitan area. This condition is most likely to occur when one of the first splitlines cuts through the metropolitan area. It is often considered a drawback of the system because residents of the same agglomeration are assumed to be a community of common interest. This is most evident in the splitline allocation of [[Colorado]].<ref>{{Cite web | url = http://www.rangevoting.org/SSHR/co_final.png| title = Untitled | website = rangevoting.org| access-date = 30 June 2021}}</ref>
However, in cases when the splitline divides a large metropolitan area, it is usually because that large area has enough population for multiple districts. In cases which the large area only has the population for one district, then the splitline usually results in the urban area being in one district with the other district being rural.

As of July 2007, shortest-splitline redistricting pictures, based on the results of the 2000 census, are available for all 50 states.<ref>{{cite web|url=http://www.RangeVoting.org/SplitLR.html|title=Splitline districtings of all 50 states + DC + PR|publisher=RangeVoting.org|access-date=5 August 2009}}</ref>