You’re goal, at the very least, is to assign population to the districts so that each district has close to the same population, and to make sure each district is cohesive (all blocks are connected). As you work with your map, it will always be saved in the cloud.
The way you assign population to your districts is to color the map.
- Select the district you want to color using the radio buttons in the left most panel.
- Use the green control on the top bar to toggle to Color Mode. Use the drop down to select the Color Unit (BG/VT or County). You can also double-click on the map top toggle Color Mode.
- In Color Mode, click the shapes on the map to color, which assigns those color units to the selected district.
- You can hold the left mouse button down and sweep to color.
- You can drag out a box and coloring everything in it. Hold Ctrl (Windows) or Command (Mac) down, then hold the left mouse button down, drag out a box and release the mouse button.
Let’s look at some of the controls and tools that can help you as you decide how to color the map:
- The top bar has the Show section. By default District Colors is checked, which will show the district color of each BG/VT that you have colored.
- Checking Partisanship Colors shows each BG/VT based on its partisanship.
- The last checkbox Demographic Colors (All Groups) shows each BG/VT by its demographics. The associated dropdown can be used to show colors by a specific demographic.
- When you hover over a color unit, a popup toward the lower left shows the data for that color unit. The position of the hover can be adjusted: click on Show (on the top bar) and change to Adjust. Click the check box to show an arrow control to adjust the position.
- The View Props button gives you options to show the background map, county lines, district labels and more, and the option to hide partisan data.
Import Existing Maps
One way to start a map is by importing an existing map.
- Some states publish block mappings (aka block equivalency) of the maps they drew in 2011, usually as CSV listing each census block id and the district to which it was assigned. After you have created a blank map, you can click the Gear icon (upper right) to take you back to Map Set Up and Auto Color. From there choose the file and click Apply, which will color the map according to that information. [Note: this currently works only for 2016 Block Group datasource.]
- From the main My Maps page, you can also import a map saved from DRA 2.2/2.5 (.drf) or saved from a previous DRA 2020 session (.json).
Your strategy as you color your map can make a big difference.
- Think about what your goals are. Are you trying to keep certain groups together? Are you trying to make a partisan map? Are you going for compactness or competetiveness or proportionality? Do you want to minimize change from the current map?
- Setting the color unit to County can allow you to color large areas quickly. You can always change the color of areas you previously colored. Also with this setting you can hover over counties to see their population, which helps you get a feel for which can be grouped and which will have to be split.
- If you have specific groups, such as minorities, that you need to keep together in a district, it’s a good idea to start there.
- Having a rough idea of where your districts should be centered can help.
- Once you start coloring, don’t try to make the first district perfect without coloring other districts. Instead, make a rough cut of each and then refine; you’ll always have to tinker around the edges to meet your target population goals.
As you get to the last blocks to color, you’ll likely be looking at the population and deviation columns, tinkering to get as close to the target as possible. There are a few other things you should do as well.
- Check cohesiveness and for unassigned blocks. To do this, click Show, and change the dropdown to Check, which will show two checkboxes. Find Unassigned will zoom in to where any unassigned blocks are. Find non-cohesive will zoom in to any disconnected portions of a district.
- Look at the Analytics by clicking Analyze Map. This will give the demographic breakdown, partisan makeup and compactness of the districts. [More analytics are under development.]
Your map is always saved in the cloud. When you’re done, you can Publish it, so everyone on DRA 2020 can see it. You can Share it with a few friends or colleagues. You can take screen shots of it and post them on your blog. You can also Export it as a .json or .csv file.