RangeVoting’s HONEST Electoral District Formula and Maps

October 27th, 2007

For all the quant jocks out there…

From their site:

The shortest-splitline algorithm for drawing N congressional districts (part of our ballot initiative)

Formal recursive formulation

  1. Start with the boundary outline of the state.
  2. Let N=A+B where A and B are as nearly equal whole numbers as possible.
    (For example, 7=4+3. More precisely, A = ⌈N/2⌉, B=⌊N/2⌋.)
  3. Among all possible dividing lines that split the state into two parts with population ratio A:B, choose the shortest. (Notes: since the Earth is round, when we say “line” we more precisely mean “great circle.” If there is an exact length-tie for “shortest” then break that tie by using the line closest to North-South orientation, and if it’s still a tie, then use the Westernmost of the tied dividing lines. “Length” means distance between the two furthest-apart points on the line, that both lie within the district being split.)
  4. We now have two hemi-states, each to contain a specified number (namely A and B) of districts. Handle them recursively via the same splitting procedure.

Asterisk: If anybody’s residence is split in two by one of the splitlines (which would happen, albeit very very rarely) then they are automatically declared to lie in the most-western (or if line is EW, then northern) of the two districts.

See high-precision computer-generated pictures for all 50 states.


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