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6

While some districts may follow block group, tract or even county boundaries, many of them (probably most -- might depend on the individual state) were based on block-level data. Since the districts have to be drawn based on Census data, and since the smallest level of geography the Census Bureau uses is the block, there should be no districts that violate ...


5

Follow-up with some other non-commercial web apps people have been developing: Florida is rolling their own MyDistrictBuilder web ap: http://www.floridaredistricting.org/ (app may be at http://floridaredistricting.cloudapp.net/MyDistrictBuilder.aspx, website claims they'll have public testing in March) Profs. Altman and McDonald are developing the ...


4

For privacy reasons, personally-identifying house-by-house data from the Decennial Census are not available until 72 years after being recorded. Census Blocks are the highest spatial resolution geography for which more recent Decennial Census data are available. If you only want Census Block populations for a couple of counties, use the Census Factfinder. ...


4

For anyone who's curious, I came up with a solution on my own, using PySAL's region.Maxp algorithm. Essentially, Max-p allows me to generate a set of regions that meets my first criterion (minimum number of employers per region), and I put that inside a while loop, which will reject any of Max-p's solutions that don't also satisfy the second criterion ...


4

Disclaimer: I'm definitely not a lawyer. The opinion is here. From skimming through it, it appears to me that the special federal court jumped the gun in producing a new map. The state's version hadn't been 'precleared' yet, but that map did not obviously violate any laws. It can still be challenged in court, but "in ordinary course." That is, a ...


3

There is Azavea's open-source District Builder. The source code is available on github.


3

There's also Maptitude for Redistricting: http://www.caliper.com/mtredist.htm


2

Just stumbled upon this blog post. Seems like Python's PySAL library can handle regionalization as well.


2

This should be a comment (as it doesn't answer your question), but was just alittle too long. Very cool application! I have never come across a situation like this, and I believe a more common route is to actually keep whatever units you decide on a priori and then use different techniques to "fudge" the data to protect privacy concerns. For an ...


2

Azavea has released a web-based, open source software for collaborative redistricting called DistrictBuilder. You might want to try it out. As for learning about redistricting, you might want to read A Citizen's Guide to Redistricting.


2

ESRI offers two products to support redistricting (as in drawing boundaries for election districts). The web-based product is described here. There's also an add-on version that is described here. As best as I can tell, the add-on is free and will work on versions 9.0 forward. Documentation and a tutorial are here. This add-on appears to be designed to help ...


1

You have some topological issues with the polygon dataset - seems there are a lot of overlapping areas. Importing the layer into GRASS (which checks and tries to fix these kinds of errors) gives: 16 areas represent more (overlapping) features, because polygons overlap in input layer(s). Such areas are linked to more than 1 row in attribute table. The ...


1

As noted by dmahr, the lowest level of data available from the Census Bureau is block level data. While it might initially sound appealing to have data which is precise to the housing unit level, this actually will only complicate production of the end product. In the picture I have included below, the blue box demonstrates the area of a typical census ...


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You might check to see if you can legally use the same mapservices that are used by Esri Redistricting Online in an application that you develop. These mapservices provide data down to the block level. For more details see this thread.


1

There's also ArcBridge's DistrictSolv tool: http://www.arcbridge.com/DISTRICTSolv.htm



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