Texas Redistricting & Workshop - Texas Redistricting

# Google Map: Redistricting in Texas

# Workshop Materials: CD Image (350mb)

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Held our library's 3rd and final workshop of the semester, entitled Congressional Redistricting in Texas: The Maps & The Demographics. It was a blast as we had 15 students, 4 staff, and 2 faculty members attending. Everyone seemed to have a good time.

The 2-hour workshop was organized into three sections.

1. Dr. Jose Gutierrez, political science faculty, first gave an outstanding 30-minute introduction to the redistricting process in Texas, with an emphasis on the 2003 Texas redistricting and the 2006 Supreme Court decision that required the Texas legislature to redesign District 23. Jose is a fantastic speaker and it I learned a lot.
2. Spent approximately 30 minutes exploring local voting results and congressional district boundaries using the UT Arlington Library: Texas Redistricting interactive map. Using the same interface design as Mapping the Afghan Experience and the developing Texas Time Machine. The Texas Redistricting Google Map (image above) incorporates voter tabulation district (VTD) election data from the 2000 & 2004 presidential elections, and the 2006 gubernatorial election. There are app. 8,500 VTDs in Texas, so the data allows for local analysis. Not quite as numerous as block groups (app. 14,500 in Texas), but still quite small.
3. Spent the remaining 45 minutes using ArcMap.
1. First, we showed everyone how to use the spatial join function to find the % Hispanic population (from block group Census data) in the infamous District 23 in the 108th Congress (before the 2003 redistricting), the 109th Congress (results of the 2003 redistricting), and the 110th Congress (results of the Supreme Court demand to redraw the Congressional district boundaries. This was quite effective as the percentage dropped over 10% from the 108th to the 109th.


2. Second, we ran through an exercise where participants adjusted the 109th Congressional Districts based on their preferences, whether they be biased or impartial. No programming was necessary for this automation. I was able to create it rather quickly using ArcMap's Model Builder. I implemented an extremely simple algorithm making use of ArcMap's built-in mean center function and then creating a simple voronoi polygon map. Now, our campus has not yet upgraded to ArcGIS 9.2, so I used the euclidian allocation function instead of the voronoi map functions included in 9.2.

So, where did all of this great data come from? Mostly from the Texas Legislative Council's Redistricting FTP Site. Note that Firefox has some issues with this FTP site, so if you use a browser to access FTP, use IE. For more details about data sources, see the workshop handout, which is basically a bibliography of relevant data sources.