Daves Redistricting — More data and fixes

Hi Everyone,

Last night I upload 2.1.2 and this morning I added 2010 data for more states.

New States: DE, KS, NE, NC, WY.

Key fixes:

— 2010 VT shapefiles are WAY SMALLER, like almost 1/10!!!

— 2008 Block Group population numbers fixed. It was most noticable in Wyoming, where the app claimed a population of 193,000.

Note: if you use Firefox, you will have to clear the cache to correctly load some states, incl. WA, MO, KS. It seems to cache the app XAP file, even when the website has a new one. IE and Safari don’t have this issue.

More below the fold.

Shapefiles: As you know from previous posts, the 2010 census VT shapes were way bigger. I was searching around on the web for help/advice/code and found MapShaper, a web app that allows one to upload a shapefile and then change it. Thank you Matthew Bloch and Mark Harrower. It appears that Matthew Bloch is now with the NY Times and responsible for some (all?) of the cool online maps they’ve been doing. I used the Douglas-Peucker simplification to simplify by 10% and whoa! the files are nearly 1/10 of the size and I bet you can’t notice the difference! I am so jazzed about this I’ve been telling anyone who will listen!

Thank you Tyler for pointing out the population of Wyoming (2008 block groups) was a bit off. This bug has been there for a while, but only shows up if the population data some block groups are split into parts. What happens is there’s only 1 shape for the block group but multiple parts in the data. I was only using population from 1 part. For most states, not that many block groups were split, but in Wyoming (and Montana) a lot of them are, making it more obvious. That’s fixed and so the 2008 BG numbers should be a lot better.

Note on Oregon. There are no VT shapes for Oregon, just like in 2000. So, I’ll have to use block groups for the 2010 data. That will take more work (some tools work, some change in the code). Not sure when I’ll get to that.

There are updates to VA and MD for election data to include some average turnouts. I will get to these next week.


14 thoughts on “Daves Redistricting — More data and fixes”

  1. Thanks again for your work. I know it’s not entirely under your control, but I wonder if there’s any chance of NJ political data? It seems like they may have their maps wrapped up pretty soon, and it would be nice to be able to analyze their proposals in an informed way.  

  2. Whenever you get around to it.

    I may have to spend too much time playing with a North Carolina map tonight, especially now that it won’t be getting that 14th district we were all counting on.

  3. I also admire the hard work you put into creating this website, but Illinois will also be finishing its redistricting later this spring if new reports are to be believed.  This is because the Illinois constitution gives the state legislature and governor (all Democratic this time around for the first time in the past few decades) until June 30 to agree on district maps for Congress and the state legislature.  If no law is signed by then, it then bounces to a non-partisan commission, and eventually to a proverbial name out of a hat (in our case, an Abe Lincoln stovepipe hat in the state archives).  Since Democrats will not want to piss away their really only chance nationwide to do damage to the GOP, I think it is a safe bet that a new map will be in place by late June.

    So, any idea when political data might be available?  I would hate for all the effort and hard work you have put into democratizing the byzantine process of redistricting go all to nought in the one true state where Democrats will pass a partisan plan in their favor.

  4. Dear Dave,

    I’ve finally gotten around to using 2.0 and what a joy!  The box is a great feature.  I also like the contiguous check, especially when I change district shapes, and the improved search for missed voter data.  I can zoom in and it stays that zoomed!

    Thank you for all your hard work in putting this web program up and running.

  5. Sometimes when I’m doing a map and use the buttons at the top left to move it just a little bit, the map won’t stop moving. Ever. I was just finishing my Maryland map when it wouldn’t stop moving. I tried everything and lost most of my work…

    Sorry if this has already been addressed…

  6. is that in redistricting California (Windows 7, Safari) when I click on a precinct, it also automatically colors in precincts miles away, that I put into other districts. I mostly see this in Kern and Santa Clara Counties.

  7. Just one question about the VA bug showing that McCain won Loudoun County. Can this be dealt with by clearing the cache or has it just not been fixed yet? (not that I’m rushing, just wondering)


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