Drawing Your Plan (Version 1.2)

After you have selected a plan to edit or view, you are directed to the Draw tab. Here, you see tools for managing what you see in the map layers, editing districts, manipulating districts, and district statistics. All of these are important features to understand as they will enable you to draw a legal redistricting plan.

Map Legend

Perhaps the first thing you may notice about your map is that districts are colored. Closer examination reveals that the counties and other geographies that underlay the districts are also shaded. These colors are intended to provide you with clues and tools that enable you to draw legal redistricting plans.

The Map Legend button on the lower right corner of the map provides a legend of the information displayed about the districts and the underlying geography. This information is described below in more detail. Essentially, there is information about the underlying geographies that you are creating districts out of and information about the districts themselves.

Map Layers

The district boundaries and boundaries of the underlying geographies they are drawn out of are known as Map Layers. Although not immediately visible when you first begin editing districts, you can overlay additional reference layers such as community maps and other redistricting plans. You can configure the map layers by clicking on the Set Map Layers icon.

Clicking on the Set Map Layers icon reveals the Choose Map Layers popup window. You have the following options

• 1. Change how the counties and other underlying geographies that you select to edit districts are shaded

  2. Change how the districts are shaded

  3. Show other boundaries as reference layers

Shading the Underlying Editable Geography

The first pull down box in the Choose Map Layers dialog box allows you to change how the editable geographies are shaded. By default, counties and other editable geographies are often shaded by their total population. The same is true for any other editable geographies such as census tracts, census blocks, or precincts and wards (the available geography is determined by the administrator). The allowable shadings will vary with the available data in each state and it is possible to turn off the shadings by selecting "None" which may be useful if you wish to create printable maps.

Typically, the underlying geography may be shaded by census and political data. In the example given here for a version of the software used in Virginia:

• • Total Pop. is the total number of persons in a district. The federal and some state constitutions require that districts have equal population -- the degree of equality depends on the type of district (congressional or state legislative) and upon state law.

  • Black VAP and Hisp. VAP is the Black and Hispanic Voting-Age Population (Black and Hispanic are Census Bureau terms). The voting age population is everyone age 18 and older. The number of minorities of voting-age within districts is an important statistic to pay attention to for districts to comply with the federal Voting Rights Act or similar state requirements. The administrator may enable shading of geographies by other racial and ethnic categories.

  • % Dem Gov. '09, Two Party is an example of election data that may be available. Typically in redistricting, statewide races are used to evaluate the underlying partisan strength of districts, which is one factor to determining which parties' candidates are favored to win within a district. By "Two Party" we mean the vote for the Democratic and Republican candidates only -- this is typical in redistricting as the vote shares for the major political parties are most meaningful to the election outcome. The administrator may enable shading of geographies for more electoral contests and votes for minor political parties.

Keep in mind that there is a lot of racial, ethnic, and political data that can be made available. These are illustrative examples used for a redistricting competition in Virginia.

You can see what the shading for the geographies means by clicking the Map Legend button in the lower right hand corner of the map editing area.

Shading the Districts

The second pull down box in the Choose Map Layers dialog box allows you to change how the districts are shaded. By default, districts are usually shaded by their total population -- and how close they are to the ideal population for that legislative body. (The ideal population is the total population of the state divided by the number of districts in the legislative body.) The administrator may enable districts to be shaded by other values, such as the districts' compactness and contiguity status. You may also choose to have no shading for the districts, which may be useful if you wish to create printable maps).

The map above illustrates how districts may be shaded. Here, districts are shaded by how close their total population is to the ideal district population. The gold (or blue) colored districts are above the ideal population, with darker colors indicating that the districts are further from the ideal. A district that is not shaded is within the population tolerance set by the administrator.

You can see what the shading for the districts means by clicking the Map Legend button in the lower right hand corner of the map editing area.

Show Reference Layers

Reference layers are geographies that can be displayed, but cannot be used directly to edit districts. You can follow the boundaries of reference layers by selecting editable geography contained within them, so they can be useful to guide you indirectly during your map making. A reason why reference layers cannot be used to directly edit districts is that that they are not guaranteed to be nested within the hierarchical geographies of the database. Allowing editing of non-nested geographies would significantly slow the performance of the software.

There are two types of reference layers, those that are editable geographies and those that are of other existing maps, be they redistricting plans or community layers.

Show Reference Layers - Editable Geographies

When zoomed in, lower levels of geography will appear for editing, for example, counties, census tracts, precincts, and census blocks. The boundaries for geographies other than the one currently editable can be displayed by choosing the available geographies in the third pull down box Choose a Reference Layer in the Choose Map Layers dialog window. The administrator selects the available reference layers for viewing.

Show Reference Layers - Legislative Districts or Community Maps

Other legislative districts or community maps can be displayed as reference layers by clicking on the Choose a: legislative district or community map reference layer button in the Choose Map Layers dialog window. Clicking this button will reveal a file manager that is similar in character to the plan chooser. From here, you can select a redistricting plan for a legislative body or a community map that either you are privately working on or that other users have shared.

To select a reference layer for display, choose one of the available map types on the Select Plan Type drop drown box. Usually these will be congressional plans, state legislative plans, and community maps. By default, congressional plans will be typically displayed.

Once you have selected a plan type, the Select Plan to Display as Reference Layer will populate with the available plans.  The plans can be sorted by the user name and plan name by clicking on the column headers, and you use the navigation buttons at the bottom of the plan list to display additional plans.

When you are satisfied with the shading of your map editing environment and the layer that you wish to display, click on the OK button to return to mapping.

If you have selected a reference layer, its name will be displayed in the Road Display Dialog Box located in the upper right hand corner of the mapping area.

Zoom and Pan Tools

The geographic layer that you can edit is tied to the zoom level. When zoomed far out, only counties will be visible for editing. As you zoom in other editable geography will become available, such as census tracts, Voting Tabulation Districts (a generic term for precincts, wards, election districts, etc.), and census blocks. We tie the editable layer to the zoom level since this avoids the problem of showing the many census blocks for an entire state -- the amount of data involved would slow the program considerably.

Pan Tool

To move the view area in a north/south/east/west direction, use the pan tool located in the upper left hand corner of the mapping area.

You may also use the mouse to pan. To do so

• 1. Click the pan tool (the hand icon on the Edit Map tools). This is the default editing tool when you first enter the mapping screen.

  2. Click on the mapping area and hold down the mouse button.

  3. Move the cursor while holding down the mouse button.

Zoom Tools

There are three ways to change your zoom level.

Zoom Slider Tool

To zoom in about out using the zoom slider tool located in the upper left hand corner of the mapping area, click on the plus or minus sign to zoom in or out, respectively. Or, click on the slider and move it to the desired zoom level.

Map Extant Tool

To quickly change your zoom level to the entire jurisdiction, click the round icon at the center of the pan tool.

Marquis Zoom Tool

This is perhaps the most useful zoom tool, and there is no associated icon to tell you it exists. To quickly zoom to an area using the marquis zoom tool:

• 1. Click the Pan tool (the hand icon on the Map Editing tools). This is the default editing tool when you first enter the mapping screen.

  2. While holding shift, click on the mapping area and hold down the mouse button.

  3. Move the cursor while holding down the mouse button.

  4. A rectangle will display on the map. This rectangle represents the area you will zoom to. When you are satisfied with the area you wish to zoom to, release the mouse button.

Road Display

Displayed underneath the districts, editable geographies, and reference layers is a map layer of roads, cities, and other features that provides helpful context to a mapping session. The administrator may make various maps available to you: Open Street Map (or osm), Google Maps, and Bing Maps. Select a preferred street map by clicking on the appropriate button on the Road Display Dialog Box located in the upper right hand corner of the mapping area. There are licensing restrictions on Google and Bing, so your administrator may choose not to make these street maps available.

You can increase or decrease the transparency level of the districts and the editable geographies by moving the roads transparency slider in the Road Display Dialog Box.

If you have selected a reference layer, its name will be displayed in the Road Display Dialog Box.

Map Tool Sets

There are two sets of mapping tools available in two tabs at the top of the mapping area. The Map Editing tools are for selecting and assigning editable geographies to districts. The District Tools are additional mapping utilities. Select tool set by clicking on the desired tab.

There are four tools that are available in either tool set, the Pan Tool and Info Tool, which are for navigating around the map.

The Pan Tool

The Info Tool

Undo/Redo Edit

Map Editing Tool Set

The Map Editing tools are for selecting and assigning editable geographies to districts. The mapping task is divided into two steps. First, editable geographies are selected and second they are assigned to districts. There are two different types of tools for this task, selection tools and assignment tools. While selection and assignment tools can be simultaneously selected, it is important to remember these are two different types of tools. If the software appears to be behaving unexpectedly, it can be often useful to review the selection and assignment tools.

Select Tools

The three Select Tools enable you to select geographies for assignment to a district. You can select individual editable geographies or collections of editable geographies, depending on which tool you use. If you attempt to select a large number of geographies with any selection tool, you will receive an error message to select fewer geographies.

When working at the census block level, it is often easy to select (and fail to select) many geographically small zero-population road and water segments, so be careful when working at this level. Often, a clue that something has happened is that you will be warned that a district is non-contiguous. We provide additional District Tools to help you with this, what can be at times, tedious task.

The Single Select Tool

The Rectangle Select Tool

The Polygon Select Tool

Assignment Tools

The heart of mapping is assigning selected geographies to a district. There are two methods that we use to perform this task, the Anchor District assignment tool and the Click and Drag assignment tool. The District Anchor Assigning Tool is also the tool that we use to create new districts, if there are still empty slots. The number of district slots is set by the administrator and typically will not exceed the maximum number of districts for a particular legislative body one is drawing districts for.

The District Anchor Assignment Tool

The Click and Drag Tool

Creating a New District

Sometimes people prefer starting from a blank map or are working for a partially completed map, perhaps because they have removed a district in a slow growing area of a state. The Anchor District assignment tool can be used to create a new district. To create a new district, you must have a free district number to assign to.

You can create a free district number by three methods:

• 1. Associate the Anchor District assignment tool to unassigned. Select all of a district's geography and change it to unassigned.

  2. Use the Unassign District tool to unassign all of district's geography in one step. See the Unassign District tool, described below.

  3. In certain circumstances an free district number may be already available. For example, such a free district may be available in a state that has gained one or more congressional districts and the starting map is the current congressional districts.   

In the example above, District 6 is available for assignment. To assign geography to a new District 6, perform the following steps:

• 1. Use a selection tool to select editable geography.

  2. From the drop down list in the District Anchor Assigning Tool select "New District" (Note that you do not first select the Anchor District assignment tool icon to perform this action.)

  3. You will be presented with a pop up window that asks which new district you wish to assign the geography to, among the available slots (in this case there is only one option, District 6). Select the district you wish to assign the geography to and click "OK".

District Tools Set

The District Tools set may be accessed by selecting the District Tools tab. These are utility tools that may be helpful to map editing.

The Lock District Tool

The District Info Tool

The Unassign District Tool

The District Copy and Paste Tool

Identifying Splits

You may wish to draw a plan that minimizes the number of times districts split geographies, such as counties, communities, or districts for other legislative bodies. The Show Splits and Generate Splits Report are useful tools to draw districts that or any boundary that can be shown as a reference layer.

Show Splits

Generate Splits Report

Highlighting Districts

Districts can be highlighted in blue by clicking on the district on the Statistics sidebar on the right hand side of the mapping screen. Highlighting districts may be useful to identify small non-contiguous pieces of geography that often occur when working at the census block level.