On 8/18/05, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > I would also like to see the district drawn by a bipartisan or > nonpartisan agency. I believe some states (Maine?) have such > a requirement. I was not sure how to define that concept however. > If anybody knows how Maine or wherever defined it, can you tell us?
> > As to rivers, what about other areas impassable by ordinary transportation? > > --I could add a few like "lakes". Basically, I want as few > exceptions as possible. The plan of convex-districts-only > permits a good deal of freedom but outlaws fractal-shaped districts > like they just drew in Texas. If they have to keep the boundaries > going straight or left in the middle of lakes, probably a good thing, > no need to let them turn right. > This whole measure will not really abolish gerrymandering > but it will keep it from being really outrageous. Warren, As with many topics, this has been covered extrensively before in the EM archives. As far as non-partisan districting goes, an idea that has gotten a lot of mileage is some sort of specific algorithm that is used to determine districts. I'll try to describe one approach below: -------------------- The "atoms" of districts are census blocks. Census blocks are drawn up in a nonpartisan fashion, and since they are much, much smaller than congressional districts, it is extremely difficult to manipulate the process by re-drawing them. Consider the census blocks in a given state to be the nodes of a graph. There are links between all nodes where the census blocks are geographically adjacent. The nodes have weights equal to the population therein. The links have weights equal to the number of lanes of transportation connecting the two nodes. A single lane of surface road is worth one. Limited access highway lanes can be made to count double or triple. Railroad and subway lines can be weighted more heavily than a single lane, and sidewalks less heavily. If the border between two census blocks is formed by a road, then any lanes that "T" into that road count half as much as usual. (So a road that cuts through counts regular.) (Note that natural boundaries such as rivers and mountains tend to have few ways to cross them, so they will naturally end up as boundaries.) If the state is to be divided into N districts, then the graph must be divided into N unconnected sub-graphs by severing links in the graph. The problem is: minimize: total weight of severed links subject to: total node weight of each of the N sub-graphs must be within 5% (or some small acceptable error) of one another. I beleive this is an NP problem, but a good genetic algorithm could come up with an acceptable solution given enough time to crank away. ---- Election-methods mailing list - see http://electorama.com/em for list info