Dave's Redistricting App

[JohnnyLongtorso]

Dave has switched to using voting districts for the maps. Since they're bigger than census tracts, it's presumably less work for him.

[Verily]

Here's Maryland de-gerrymandered. This map is actually awful for the Democrats because their vote is very "naturally packed" in Maryland. The map results in three moderately Republican districts (R+5 to R+10), one moderately Democratic district, and four ultra-Democratic districts (D+20 or more). A Republican gerrymander could probably make the Baltimore County district at least vulnerable.

[muon2]

Who does this map pair? It looks like Halvorson and Biggert, would that be accurate?

Where do Quigley and Gutierrez fall in the two earmuff successor districts?

I did some research and saw that Melissa Bean now has a Cook County district and Bill Foster is in the district to the west.

I think the northern earmuff is the Puerto Rican district, and the red district by the stockyards is the Mexican district, so I'd guess Gutierrez has the northern district.   The question then does the Mexican district have enough US adult citizens to be an effective minority majority district.

The standard in Bartlett v. Strickland uses a threshold of 50% of the voting age population. Argument before the SCOTUS raised the question of non-citizens, but the opinion used voting-age population. The app only had population, but I am confident that my percentages are sufficiently above the threshold so the the voting-age standard would also be met.

I started the map by drawing the two Latino districts. New CD 4 (red) is 62% Hispanic and CD 5 (yellow) is 56% Hispanic. New CD 4 gets its additional population from the parts of current CD 3 in Chicago and Berwyn, Stickney and part of Lyons Township in Cook County. New CD 5 takes the northern muff from old CD 4 plus neighboring Chicago areas and suburban Leyden Township from old CD 5 as well as the heavily Hispanic areas in northeast DuPage from current CD 6. I think it is hard to see something significantly different from these two districts drawn without a legal challenge. Gutierrez has talked about retirement in the last couple of cycles, so they could well also both be open in 2012. Quigley's old county district is almost entirely out of this new CD 5.

Next I drew the three Black districts, all of which needed to add substantial population to meet the new district size. New CD 1 (blue) is 53% Black, CD 2 (dark green) is 57% Black, and CD 7 (grey) is 54% Black. CD 7 was drawn first and had to add most of its new population along the lakefront since an expansion into suburban Cook would bring the population dangerously close to 50%. To add enough population new CD 1 picks up White areas of Chicago and Worth Township from current CD 3 and then swaps some with current CD 2 to stay above 50%. CD 2 has the easiest expansion path to the south and easily stays above 50%. As with the Latino districts, and other than some swaps between CDs 1 and 2, I have a hard time picturing any substantial departure from these districts.

With those five districts largely locked in place the other districts and options become clearer. The new CD 3 (purple) is more current CD 13 and both Lipinsky and Biggert live in that district. Given the need for the minority districts, the new CD 3 largely has to move into current 13 or 11 and will likely be a competitive district in 2012. Halvorson actually lives in CD 2 as I've drawn it, but a move elsewhere in the district would not be hard. I've also drawn both Quigley and Schakowsky into the new CD 9 (light blue), though I could see a gerrymander that puts Schkowsky and the city of Evanston in the new CD 10 (pink) and moves CD 5 out to the suburbs by O'Hare.

[JohnnyLongtorso]

Colorado:



CO-01 (gray, Diana DeGette - D) - Chopped off the northeastern part of Denver and added some of the suburbs. Remains solid Dem.
CO-02 (green, Jared Polis - D) - Drops the Weld County portion of the district and extends west to take in some of the Republican rural counties and south to the Denver suburbs and Park County. Should remain a Democratic district.
CO-03 (blue, John Salazar - D) - Removed a few heavily Republican counties. Maybe slightly more Democratic now.
CO-04 (purple, Betsy Markey - D) - Removed all the heavily Republican rural counties on the eastern third of the state. Added parts of Adams and Denver. Should be significantly more friendly to the Democrats now.
CO-05 (red, Doug Lamborn - R) - Takes in some of the Republican counties from CO-04, but since they're sparsely populated it shouldn't shift the population base much.
CO-06 (yellow, Mike Coffman - R) - Same as above.
CO-07 (teal, Ed Perlmutter - D) - Drops most of the Adams County portion and adds part of Denver to make the district more Democratic.

[Verily]

Here's my take on Colorado. Basically, Betsy Markey is less vulnerable, John Salazar is more vulnerable, Jared Polis is less safe but still safe, and Mike Coffman is now a little bit vulnerable. CO-07, CO-01 and CO-05 are largely unaffected in partisanship. Although CO-07 changes its shape dramatically, few actual voters have been moved; CO-05 does actually lose a lot of voters to the west and picks them back up to the east. CO-01 loses the northern extension of Denver and the inner southern Arapahoe County suburbs and instead has some eastern Arapahoe County suburbs that are otherwise difficult to pair with any district without some contortion. Generally, I think this map is very fair, given the population shifts.

[Kaine for Senate '18]

A 12 District Virginia:


VA-01: 72% White, 20% Black, 1% Asian, 4% Hispanic, 4% Other
VA-02: 68% White, 18% Black, 4% Asian, 5% Hispanic, 5% Other
VA-03: 47% White, 44% Black, 1% Asian, 4% Hispanic, 4% Other
VA-04: 52% White, 39% Black, 2% Asian, 3% Hispanic, 4% Other
VA-05: 69% White, 24% Black, 1% Asian, 2% Hispanic, 4% Other
VA-06: 85% White, 8% Black, 1% Asian, 3% Hispanic, 3% Other
VA-07: 63% White, 27% Black, 3% Asian, 4% Hispanic, 3% Other
VA-08: 61% White, 10% Black, 10% Asian, 15% Hispanic, 4% Other
VA-09: 92% White, 3% Black, 2% Asian, 2% Hispanic, 1% Other
VA-10: 76% White, 8% Black, 6% Asian, 7% Hispanic, 3% Other
VA-11: 57% White, 9% Black, 17% Asian, 13% Hispanic, 4% Other
VA-12: 57% White, 17% Black, 7% Asian, 16% Hispanic, 3% Other

[Verily]

I have two version of Virginia to present to you tonight.

The first was basically just cleaning up the current map, with the only major changes happening in the Hampton Roads area (basically, Norfolk and Hampton are now completely in Nye's district except for one voting precinct in Hampton, and Virginia beach is almost entirely in Forbes's district in order to both make both safer and allow Forbes's district to contract into just the Hampton Roads area and not snake over to the Richmond suburbs for population. (Also, I have no idea where in Chesapeake Forbes lives, so he may have ended up in Nye's district, although that would be easy to fix.)

The second hit me after I finished the first version, when I realized what a golden opportunity those Democratic-voting counties in eastern rural Virginia were for shoring up Tom Perriello and when I was annoyed with how long and spindly Bob Goodlatte's district had become. It only rearranges three of the eleven districts, but it makes Perriello, well, not safe, but reasonably secure in a district that may have voted for Obama, and it makes Goodlatte's district much more compact.

For those interested in the splitting of Roanoke City, I made the probably safe assumption that Goodlatte does not live in one of the majority-black precincts, all of which I gave to Boucher.

[JohnnyLongtorso]

I have two version of Virginia to present to you tonight.

The first was basically just cleaning up the current map, with the only major changes happening in the Hampton Roads area (basically, Norfolk and Hampton are now completely in Nye's district except for one voting precinct in Hampton, and Virginia beach is almost entirely in Forbes's district in order to both make both safer and allow Forbes's district to contract into just the Hampton Roads area and not snake over to the Richmond suburbs for population.

The second hit me after I finished the first version, when I realized what a golden opportunity those Democratic-voting counties in eastern rural Virginia were for shoring up Tom Perriello and when I was annoyed with how long and spindly Bob Goodlatte's district had become. It only rearranges three of the eleven districts, but it makes Perriello, well, not safe, but reasonably secure in a district that may have voted for Obama, and it makes Goodlatte's district much more compact.

For those interested in the splitting of Roanoke City, I made the probably safe assumption that Goodlatte does not live in one of the majority-black precincts, all of which I gave to Boucher.

My map at the top of the page is remarkably similar to your second map -- VA-09 looks to be one or two voting districts different, but is virtually the same, and we both had the same double-armed approach for Perriello and Cantor's districts. I would never put Poquoson and York in a district with a Democrat, though.

[Verily]

There are precincts in Newport News that are bigger than and as Republican as Poquoson. York's not all that Republican, either. Nye's district is easily D+8 on my map; you forget that it includes all of Norfolk and almost all of Hampton.

Anyway, you appear to have left Fredericksburg out of Perriello's district in favor of Danville and Henry County, but those areas are trending away from the Democrats while the Fredericksburg area is becoming much friendlier to the Democrats, especially Perriello-types (while Perriello is really too intellectual to get much traction in southern/southwestern VA).

[JohnnyLongtorso]

There are precincts in Newport News that are bigger than and as Republican as Poquoson. York's not all that Republican, either. Nye's district is easily D+8 on my map; you forget that it includes all of Norfolk and almost all of Hampton.

Anyway, you appear to have left Fredericksburg out of Perriello's district in favor of Danville and Henry County, but those areas are trending away from the Democrats while the Fredericksburg area is becoming much friendlier to the Democrats, especially Perriello-types (while Perriello is really too intellectual to get much traction in southern/southwestern VA).

Fredericksburg is a Democratic city, but the surrounding counties of Spotsylvania and Stafford (despite Obama cutting the margin) remain solidly Republican. They're a guaranteed vote in the mid-50s for just about any non-joke Republican. I've got another map in the works that does something different from either approach for VA-05 which I will post tomorrow morning.

[muon2]

My take on CO tried to minimize county fragments while bring population deviations down to 100 or less. Presumably, adjustments at the block level could get perfect equality without significant change to the map. While I only split 4 counties while maintaining some compactness, I also note that the result is remarkably similar to the current map. The major difference is that Aurora and Arapahoe County move to CD 7 from 6 and 1, and Lakewood moves into CD 6 from 1.



Edit: I switched to a split of El Paso as suggested in the comments that followed this original post.

[jimrtex]

My take on CO tried to minimize county fragments while bring population deviations down to 100 or less. Presumably, adjustments at the block level could get perfect equality without significant change to the map. While I only split 4 counties while maintaining some compactness, I also note that the result is remarkably similar to the current map. The major difference is that Aurora and Arapahoe County move to CD 7 from 6 and 1, and Lakewood moves into CD 6 from 1.

This is a good map.  I'd drop the split of Lake County, you can't get from Lake to Pitkin in the winter.  Go ahead and take a few 1000 from southern El Paso instead.

[JohnnyLongtorso]

Bipartisan incumbent protector:



VA-01 (blue, Rob Wittman - R) - Wittman picks up all of Stafford and part of heavily-Republican Hanover and loses some of the counties that went for Obama, and the parts of Williamsburg and Newport News as well. Also picks up the more Republican part of Hampton from Glenn Nye, as well as the Eastern Shore. This may seem weird, but while the Eastern Shore is not physically connected to VA-01, it is culturally much more like parts of the district than Virginia Beach.
VA-02 (green, Glenn Nye - D) - Dropping the Republican parts of Virginia Beach and Hampton and picks up all of Norfolk, Portsmouth, most of Suffolk and the minority-heavy part of Chesapeake. I've actually gotten it to a coalition district, as it's 49% white. Should be a safe district now, although Nye may not be safe from a primary challenge from the left unless he moves left accordingly.
VA-03 (purple, Bobby Scott - D) - Ladies and gentlemen, may I present a contiguous VA-03. Removing the Southside Hampton Roads parts of the district, I've added all of Newport News, Sussex/Greensville/Emporia, and Petersburg and the black parts of Hopewell. Remains 53% black.
VA-04 (red, Randy Forbes - R) - Losing the black parts of Chesapeake and parts of the district given to Bobby Scott, and adding the Republican parts of Virginia Beach and more of Chesterfield should make Forbes' district more Republican.
VA-05 (yellow, Tom Perriello - D) - District shifts north to Northern Virginia. Dropped all the southern part of the district and pushed it up north to Prince William. The tradeoff for Perriello is having to run in the expensive DC media market.
VA-06 (Bob Goodlatte - R) - Didn't change this district much, it just shifted south a bit.
VA-07 (grey, Eric Cantor - R) - Cantor's district is possibly even more Republican now, taking in much of the heavily-Republican Southside counties and a few Democratic counties out of Wittman's district instead of pushing northwest towards the Shenandoah Valley.
VA-08 (light purple, Jim Moran - D) - Alexandria, Arlington, and eastern Fairfax. Safe Democratic.
VA-09 (light blue, Rick Boucher - D) - Picks up Danville and drops the Ronaoke area. Not much you can do for Rick.
VA-10 (magenta, Frank Wolf - R) - Dropping Prince William and going west into the Shenandoah Valley should make this district more Republican.
VA-11 (light green, Gerry Connolly - D) - Western Fairfax, should be safe Dem.

[muon2]

My take on CO tried to minimize county fragments while bring population deviations down to 100 or less. Presumably, adjustments at the block level could get perfect equality without significant change to the map. While I only split 4 counties while maintaining some compactness, I also note that the result is remarkably similar to the current map. The major difference is that Aurora and Arapahoe County move to CD 7 from 6 and 1, and Lakewood moves into CD 6 from 1.

This is a good map.  I'd drop the split of Lake County, you can't get from Lake to Pitkin in the winter.  Go ahead and take a few 1000 from southern El Paso instead.

I've driven Independence Pass (12,093 ft) between Piktin and Lake so I know what you are saying about the connection. Actually, my preference was to split Custer, but the voting districts didn't provide fine control to get to my target of a 100 person deviation. With block-level projections, that's probably where I'd go.

[jimrtex]

This is a good map.  I'd drop the split of Lake County, you can't get from Lake to Pitkin in the winter.  Go ahead and take a few 1000 from southern El Paso instead.

I've driven Independence Pass (12,093 ft) between Piktin and Lake so I know what you are saying about the connection. Actually, my preference was to split Custer, but the voting districts didn't provide fine control to get to my target of a 100 person deviation. With block-level projections, that's probably where I'd go.

My quality measure for a county split would be the relative size of the smaller fragment to the population of the county.  I'd still go for a couple thousand from El Paso rather than splitting either Lake or Custer counties.

The election officials in larger counties are going to be able to handle multiple legislative districts, and probably have an integrated GIS system to draw updated precincts.  A smaller county might have hand drawn maps, and the only reason they have precincts is to match up with the comissioner districts.

[muon2]

This is a good map.  I'd drop the split of Lake County, you can't get from Lake to Pitkin in the winter.  Go ahead and take a few 1000 from southern El Paso instead.

I've driven Independence Pass (12,093 ft) between Piktin and Lake so I know what you are saying about the connection. Actually, my preference was to split Custer, but the voting districts didn't provide fine control to get to my target of a 100 person deviation. With block-level projections, that's probably where I'd go.

My quality measure for a county split would be the relative size of the smaller fragment to the population of the county.  I'd still go for a couple thousand from El Paso rather than splitting either Lake or Custer counties.

The election officials in larger counties are going to be able to handle multiple legislative districts, and probably have an integrated GIS system to draw updated precincts.  A smaller county might have hand drawn maps, and the only reason they have precincts is to match up with the comissioner districts.

In that case, I would keep Park intact and use a bit of NW El Paso for CD 6 (teal) instead.

[JohnnyLongtorso]

Alabama with two majority-black districts:



AL-01 (purple, Jo Bonner - R) - Removing Mobile and adding the heavily-Republican southern counties has probably made this one of the most Republican districts in the country.
AL-02 (blue, Bobby Bright - "D") - Added all of Montgomery and stretched it west in order to make this district the primary majority-black district in the state. It is 56% black, 39% white. Bright would almost assuredly get knocked out in the primary by a black Democrat, who might actually vote with the Democrats sometimes.
AL-03 (yellow, Mike Rogers - R) - Of course, the sacrifice here is that Rogers' district is pretty much unwinnable for the Dems now. Removing the parts of Montgomery in the district has dropped the black population from about 32% to 24%.
AL-04 (teal, Robert Aderholt - R) - This district didn't change very much, although it did take in the northern hook of AL-06. Very, very, very safe Republican.
AL-05 (grey, Parker Griffith - "D") - Also didn't change this one much. Can't say I care what happens to Griffith at this point.
AL-06 (red, Spencer Bachus - R) - Loses the aforementioned northern hook around Birmingham and moves a bit to the southeast, which is not going to hurt Bachus any.
AL-07 (green, open) - This is what remains of Artur Davis's seat after giving a lot of it to AL-02. Takes in more of the Birmingham area to compensate, but remains 52% black, 43% white.

[Brittain33]

If you were to reduce the blue district to 51%-52% African-American, how might that tidy up the lines? Not that it isn't an impressively acceptable gerrymander as it is... Is there any way to trade the SE corner to that district so the yellow district doesn't extend that far south?

[JohnnyLongtorso]

If you were to reduce the blue district to 51%-52% African-American, how might that tidy up the lines? Not that it isn't an impressively acceptable gerrymander as it is... Is there any way to trade the SE corner to that district so the yellow district doesn't extend that far south?

It's possible, but unfortunately my map didn't save in the app so I don't have it available to play around with.

[muon2]

If you were to reduce the blue district to 51%-52% African-American, how might that tidy up the lines? Not that it isn't an impressively acceptable gerrymander as it is... Is there any way to trade the SE corner to that district so the yellow district doesn't extend that far south?

It's possible, but unfortunately my map didn't save in the app so I don't have it available to play around with.

My guess is that it would be hard to move the SE corner since Houston County is roughly 100 K. You would have to see what that does to your CD 2 percentages.

[muon2]

If you were to reduce the blue district to 51%-52% African-American, how might that tidy up the lines? Not that it isn't an impressively acceptable gerrymander as it is... Is there any way to trade the SE corner to that district so the yellow district doesn't extend that far south?

It's possible, but unfortunately my map didn't save in the app so I don't have it available to play around with.

My guess is that it would be hard to move the SE corner since Houston County is roughly 100 K. You would have to see what that does to your CD 2 percentages.

I took a look at the AL map on the App, and found a way to solve the SE corner issue, keep both black-majority CDs, and minimize county splits to make nicer district lines. All districts are within 200 persons of the ideal size. The Birmingham district is 57% black and the Montgomery-Mobile district is 52% black. CD 1 connects western Mobile County to the rest of the district through Dauphin Island and the ferry to Fort Morgan in Baldwin County.

[Hash]

Any ways to gerrymander Alabama so there is NO black-majority district? I know it's illegal, but just for fun.

[JohnnyLongtorso]

Easy peasy. It even looks like a reasonable map:



Districts 1-5 are 29-33% black, 6-7 (the top two) are 11-14% black. When the black population is concentrated in a band in the middle third of the state, it's easy to dilute their voting strength.

As a bonus, here's MS under the same auspices:



The non-red districts are 36-38% black, the red one is 32% black.

Edit: Mississippi is harder to draw since there's a higher proportion of black voters and a fewer districts to spread them out over. This is kind of fun, in a perverse sort of way. I may do the rest of the Southern states available on the app.

[muon2]

The other interesting task is to see how close in population the districts can be without splitting any counties. MS has lots of counties and few districts, so it's possible to get quite close. This is my version maintaining one black district. The four deviations are -339, +143, -165, +363. Note that the map converter has obscured the image somewhat, and Walthall and Marion Counties are in CD 3 (purple)

[JohnnyLongtorso]

Another flagrant violation of VRA:



Green 35% AA, blue and red 33%, yellow 30%, purple 28%, teal 21%, grey 14%.