[Update 10/13 3:41 PDT: the Hispanic data for California, Kentucky and Wisconsin was incorrect. I've now uploaded the correct data. Thanks to CalifornianInTexas and nico for noticing.]
My time coming, any day, don't worry about me, no
...
California, preaching on the burning shore
California, I'll be knocking on the golden door
Like an angel, standing in a shaft of light
Rising up to paradise, I know, I'm gonna shine
David asked me to do a quick example of how I do my redistricting, so I decided to use a relatively 'easy' state, Wisconsin, since it has townships. In the same way I wouldn't drive a car or ride a bike without brakes (yes, fixie riders, the laws of physics hate you too), I don't want to redistrict without having both sets of information.
Before you start, take a look at the state, and try to think how much detail you're going to want to go into. I usually do townships/municipalities when available, but sometimes precincts. For Wisconsin, I'm going shooting for 7-1, by making the 1st and 6th more Democratic. Wisconsin doesn't have precinct-level census data, so we'll have to stick with townships. I really do want to split the city of Milwaukee though, so we're going to do some estimating in just a little bit.
So now, here's a quick overview of the process ahead:
1. Collect political and population data
2. Aggregate data together into one spreadsheet
3. Prepare a GIS shapefile (we'll get into that) for the precinct and precinct-equivalents we're going to use.
4. Import data from the spreadsheet into shapefile
5. Redistrict!
This redistricting map has really been a long time coming, but trying to match up the 36,000 census blocks of NYC and the 20,000 blocks of Nassau County (among many, many others) with a precinct and creating a consolidated population-political data file tends to take a while. But unquestionably, I also think this is my best map yet. I used 2008 population estimates by city/town, projected forward to 2010. I also worked painstakingly hard for population equality, which I think is evident in that the total deviation for all 28 districts is 86, or 0.012% of a single district.
At a whopping 26-3, our NY delegation is already pretty maxed out. With the loss of a district in 2010, there's a good opportunity to consolidate and create what could possibly be a 27-1 delegation. I chose to do this by eliminating John McHugh's district and then employing some old-fashioned cracking of Nassau County to defeat Peter King. Side goals included strengthening Massa, Arcuri, Murphy, Hall, and McMahon, while preserving VRA districts for Meeks, Towns, Clarke, Velazquez, Rangel, and Serrano.
I've just uploaded a change that allows the application to use voting districts in addition to block groups, as the building blocks for drawing redistricting maps. This is a step toward getting partison data (specifically the 2008 presidential vote) into the app, because voting district partisan data is available for many states. That will require a bit more work, but will be coming soon.
I've added 6 new states, all using voting districts: Alabama, Colorado, Illinois, Maryland, Mississippi and Virginia. I added voting districts to the existing state Georgia, so it supports both. If you have saved DRFs, you'll need to keep using block groups on those files.
Johnny beat the annoucement that New York is ready, with a great map. (Nice going!)
I've also made a couple of improvements to the software, prompted by working with New York:
- Thinner block lines, so you can see the tiny blocks.
- The slow work of Assign Old CDs now happens when you click the button instead of on load. (It took about 4 minutes for NY on my not too slow machine.)
- Zoom: Scrollbar replaces slider.
First, let me say that I'm impressed by the many redistricting maps many of you have created recently. I'm happy that you have found my application useful. It's been fun working on it and it makes it so worthwhile to see what you all are doing with it.
Today I uploaded an updated application with these new features, all of which are requests from those of you who have emailed me. They are...
Lately there has been a lot of Debate over the number of Democratic Congressional Districts that Democrats could gerrymander out of the state of Michigan if they had complete control (right now they hold the Governorship and State House. They stand a good chance at taking control of the State Senate while the Governor's race is a tossup). A few people, namely IHateBush, have said that it is possible to succesfully draw a map that would yield 12 Democratic seats and only 2 Republican seats. I've been trying for several weeks to draw a 12-2 map, meanwhile protecting endangered incumbents (specifically Schauer) and I've determined that a 12-2 map would be far overeaching and in a neutral or Republican leaning year might end up 9-5 or worse. I think the best Michigan Democrats could do is create 11 safe or Democrat leaning districts and 3 strongly Republican districts. I've drawn a map that I think does just that, although I still am not entirely confident that we could hold both of my "Thumb" districts in a Republican year. But without further ado, here's my map.
I decided to try redistricting in my home state of Colorado a while back, and after many many tries, I was able to put this together. I know its been done, but mine is a little different.
I used the 2007 estimates to put it together, since the 1st, 7th, 3rd, and 2nd won't have enough people as they are to remain intact anyway.
This map is assuming democrats continue to control both houses and the governor's mansion, luckily its not likely that we lose any of the three.
My first goal was also making Markey safe, she's a great representative, especially for such a traditionally red district, so wanted to pull her district out of the swingiest territory. Second was changing the 3rd enough so that Obama would have won it, just shoring up Salazar some and keeping it really swingy, preventing most Colorado Republicans from winning there because they have moved so far to the right.
With the 7th and 1st I wanted to make them more compact and make the 7th just safe no matter what, and wanted to dillute the blueness of the 2nd for the benefit of the 3rd.
And then I tried to pack as many Republicans into the 5th and 6th as possible.
During the past eight years, Iowa has gained as many people - about 76,000 - as states like South Carolina and Virginia gained between 2007 and 2008 alone.
To retain the congressional seat, the state would have to gain nearly twice that number by 2010, according to projections by Election Data Services, a Washington, D.C.-based consulting firm that analyzes the impact of demographics on politics.
So, Iowa will be left with four Congressional districts. No one knows what the new map will look like, but it's likely that the 2012 race in the new third district will determine whether Iowa Democrats (who now hold a 3-2 edge in U.S. House seats) gain a 3-1 advantage or have to settle for a 2-2 split.
