Local Redistricting
Local redistricting involves the redrawing of boundaries of local election districts; these could be county councils, school boards, city councils, judicial districts and more.[1]
While DRA 2020 was designed for statewide congressional and legislative redistricting, it is the case that some of our users create local district maps with DRA. Here is one approach to do that.
Start a New Map
Lycoming County, PA has six Magisterial Districts. First create a new map, just like you would in the ordinary course. From My Maps, click the New Map button at the upper right, name the map and select PA as the state. Map Settings will automatically default to a District Count of 18, which is the state’s current number of congressional districts. Lycoming has six Magisterial Districts, but change District Count to seven — not six. (The explanation for that is coming.) Note the the target population of each district recalculates to 1.8 million. That is the case because DRA 2020 always assumes a statewide redistricting of the entire PA population. Just ignore the 1.8 million figure.
Next in Data Selector, choose Total Population 2018 and Voting Age Pop 2018, because you are doing some pre-planning for 2021 districts based on the upcoming 2020 Census results, and 2018 population data is likely closer to 2020 than it is to 2010 data. Click Apply, and DRA 2020 renders a blank statewide map.
Create a Very Discernible Border
To get your bearings and locate Lycoming County, turn off Precinct Lines in Overlays and turn on County Lines and Labels.
Once you locate the county, center it and zoom in a bit.
Next, you will start painting districts, but to start, select District 7 in District Selector — not District 1. Then, create a single temporary District 7 that includes every county that borders Lycoming County. (You will need to select County in the Paint Map tool.) This approach creates a really vivid border around Lycoming, which is super helpful in that once you began to create the magisterial districts, you many choose to show the background map, district lines, and city lines, causing the map to get quite busy. With District 7 in place, you will not inadvertently meander outside the county, especially once you lock District 7.
Determine Target District Populations
Hover your cursor over Lycoming County and look at County Details to the right. You will see the county has a 2018 total population of 114,859. Thus, each of the six magisterial districts has a target population of 19,143. Write that number down.
Paint the Six Districts
At this point, paint your districts just like you would ordinarily do. In Overlays, you will want to turn on Precinct Lines. And you may also want to turn on City Lines, as you try to minimize city splits. Select District 1 in District Selector, select Precinct in the paint tool, and paint away. Track the population of each district in District Selector, but pay no mind to what is showing as Deviation. Build each district as close as you are able to your target population of 19,143.
Validating the Map
Typically, once you are satisfied with your map, you would look at Statistics to confirm your population deviations are within an acceptable range. DRA 2020 uses a maximum threshold of +/- 10% for local maps. However, while Statistics does provide accurate population and demographic data for your six districts, deviation calculations are not accurate; just ignore them.
Instead, to validate your map, drop the district populations into a spreadsheet, and calculate the map’s population deviation by dividing the difference between the largest and smallest districts by the target population of 19,143. (Or — and now I am dating myself — whip out your handy HP 12C calculator to do the same. Long math by hand works well too.)
Remove the Border
Once you are satisfied with your map, remove the District 7 border. Click the settings gear in the upper right corner, and in Map Settings change the District Count from 7 to 6, and click Apply. The highest numbered district is eliminated, which is why the border was initially created with District 7. After your reduce the District count, refresh your browser. Select District Labels in Overlays and your county map is complete.
[1] The League of Women Voters of CA has put together a pretty nice California Local Redistricting Toolkit, that also addresses local redistricting more broadly.
