Table of Contents

Using the District Explorer Help Manual

The District Explorer Help Manual opens in your browser. The interactive Table of Contents provides easy links to topics you choose. You can use your browser's back and forward buttons to navigate the document and search feature (Ctrl + F) to search for key words. A handy Back to top link appears after many topics.

For technical assistance or defects...

District Explorer requires a broadband Internet computer with JavaScript and District Explorer pop-ups enabled, a mouse, and display resolution of 1024 x 768 or higher. See Computer Requirements for instructions on setting your browser to allow District Explorer pop-ups.

If you experience technical troubles using District Explorer, read related topics in this manual first. If Help does not solve the problem, you can request technical assistance by sending a message to

Please report defects or unexpected results by sending a message to


District Explorer is an Internet application for viewing maps of Florida's districts, political jurisdictions, and geographic boundaries along with demographics from the 2010 Census and the American Community Survey. Using District Explorer, legislators and citizens can navigate interactive maps, explore population characteristics, and create maps in PDF format.

District Explorer provides a limited set of tools for viewing district maps and Florida demographics. The simple design makes it easy to learn and use.

District Explorer does not require a login or account. It is the quickest and easiest way to view maps submitted by Senators, Representatives, and the public. Each redistricting plan listed on the Florida Senate website under Submitted Plans has its own Plan Details page with single-click access to view the plan in District Explorer.

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District Explorer interface

District Builder launches with:

The interface includes a Layers Manager in the left pane and an Interactive Map in the right pane.

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Layers Manager

The Layers Manager controls which geographic features are visible on the interactive map. Visibility of some features is scale-dependent. For example, neighborhood roads do not appear until you zoom in sufficiently.

District Explorer opens with the plan you select. Its name appears at the top of the Layers Manager panel. Clicking the plan's name opens the Plan Details webpage, providing direct access to reports, downloads, and PDF maps. In many cases, you will have used the Plan Details page to launch District Explorer and it already will be open on your computer desktop.

Color Fill Background

The Layers Manager provides four choices for Color Fill Background. Use the radio buttons to pick one of the choices.

  1. Districts fills the map based on district colors, making it easy to visualize which areas have been assigned to which districts.
  2. Value Ramp is one of two complementary methods for showing Census demographics on the interactive map (the other is Data Labels). Future releases of District Explorer will extend the Value Ramp feature to include many more choices for showing spatial data on your map. The "set" link will open a dialog to customize what demographic data are used for coloring the map. Currently, the default setting (Black-Hispanic VAP) is the only one available.
    The default Value Ramp shows concentrations of Black and Hispanic Voting Age Population from the 2010 Census in 15% increments. As the legend indicates, areas with higher percentages of Black VAP are depicted with brighter colors of red and areas with higher percentages of Hispanic VAP are depicted with brighter colors of blue. Areas with significant percentages of both Black and Hispanic VAP are shades of purple.

    At statewide and regional map extents, colors are rendered based on Census block group percentages. As you zoom to Map Scales less than 1:40,000, however, colors are rendered based on block percentages.
  3. Cities fills municipalities in various colors, making it easier to distinguish municipal boundaries.
  4. Street Map fills the map with blue waters, green open spaces, and beige cities. With color roads turned ON, the appearance is similar to Google Maps or Bing Maps.
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Census Lines and Reference Lines

Use check boxes to toggle line features ON or OFF. For Definitions of Census geography, see Definitions. Water bodies are a special case. They are symbolized with transparent blue fill, not lines.

Visibility of Census Lines and Reference Lines is determined not only by what is checked but also by the Map Scale. The layer you check ON or OFF will appear or disappear if your map is zoomed in sufficiently (features that would clutter the map and slow performance do not appear). For example, VTD, Block, Tract, and Block Group do not appear when zoomed out too far. If one of these layers is checked ON and you cannot see it, try zooming in.

By default, County, Roads, Waters, and Districts are set ON.

Checking "Districts" shows bold black outlines around districts in your selected plan (with Value Ramp, Cities, or Street Map selected as your Color Fill Background, this is the only way to see district boundaries for the selected plan). Black district numbers appear if and only if "Districts" is checked both under "Reference Lines" and under "Feature Labels (names)."

Checking "2002 Senate," "2002 House," or "2002 Congress" shows bold red, blue, or green outlines around current districts. This helps show differences between current and proposed districts. Red, blue, or green district numbers appear if and only if "Districts" is checked under "Feature Labels (names)."

Wide road lines sometimes interfere not only with Census Lines symbology but also with the background Value Ramp colors. Try toggling Roads OFF to make other features easier to see.

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Feature Labels (names)

Use check boxes to toggle Feature Labels (names) features ON or OFF. As with Census Lines and Reference Lines, visibility of Feature Labels is determined not only by what is checked but also by the Map Scale.

Being able to toggle Feature Labels ON or OFF independent of the associated line symbology is a useful feature. For example, if you want Roads to be less prominent on your map, try checking Roads Reference Lines OFF, VTD and Block Census Lines ON, and Roads Feature Labels ON. Road markers and names remain to help orient your map, but the wide lines disappear.

Data Labels

Data Labels is District Explorer's second method for showing Census demographics on the interactive map (the other is Value Ramp). Future releases will extend the Data Labels feature to include more choices for labeling your map. The "set" link will open a dialog to customize what is labeled. Currently, the default setting (Total Population, 2010 Census) is the only choice.

The default Data Labels setting is Total Population from the 2010 Census. Map Scale determines which Census geographies are labeled:

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Map Scale

A text box at the bottom of the Layers Manager shows the Map Scale of your interactive map. District Explorer can show map scales as wide as 1:4,500,000 and as close as 1:1,000. A Map Scale of 1:1,000 means one inch (or centimeter if you prefer) on the screen covers 1,000 inches (or centimeters) on the ground. As you zoom in, the number gets smaller. As you zoom out, the number gets larger.

As you zoom in and out of the interactive map, you see different map detail. What appears is controlled by: (1) which layers are toggled ON or OFF and (2) the Map Scale. Practice zooming in and out with different layers toggled ON or OFF to discover how District Explorer presents its vast store of geographic and demographic information on the Interactive Map.

You can type a number between 1000 and 4500000 in the text box. The interactive map will zoom to the scale you enter.

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Interactive map and toolbar

The Toolbar is in the upper left corner of the interactive map. It includes tools to navigate the interactive map, query Census data, measure distances, print maps (PDF), view the legend, view this Help manual, and get aerial images from Google Maps.

The toolbar includes eleven buttons. Most buttons call operations directly (Find, Full Extent, Legend, Print Map, Help, and Google Maps). Clicking one of these tools invokes the requested feature immediately. For example, clicking "Find" launches the Find pop-up and clicking "Full Extent" returns the interactive map to its full statewide map extent.

Clicking one of the five mode buttons does not have any immediate effect (other than changing the button icon to its depressed state). The mode you select determines how your cursor and mouse clicks affect the interactive map. The modes are: Zoom In, Zoom Out, Pan, i-Tool, and Measure. The mode you select stays in effect until you choose another mode.

The Find tool opens a dialog for zooming the map to the location you choose. First, pick one of the five serach criteria (District, ZIP, City, County, or Bounding Box). Next:
  • For District, type a valid district number for the selected plan. You also can zoom to 2002 congressional, state senate, or state house districts by typing the letter "c" or "s" or "h" and the district number (e.g., Find "h4" zooms to the area in Santa Rosa and Okaloosa counties containing the current House District 4). Click "Find" to zoom to selected district.
  • For ZIP, type a valid 5-digit ZIP Code and click "Find" to zoom to selected location.
  • For City, start typing a city name and make your choice from the list that appears, then click "Find" to zoom to selected city.
  • For County, start typing a county name and make your choice from the list that appears, then click "Find" to zoom to selected county.
  • For Bounding Box, the "Find what" text box shows the current map location. You can copy that text into your clipboard. Then, to locate the same position in another instance of District Explorer (e.g., another plan), paste the text into the "Find what" text box and click "Find." You also can paste the text into a spreadsheet, tag it, and save it for future retrieval (e.g., "Florida Mall area", "-81.405,28.436,-81.382,28.455").
The Full Extent tool returns the interactive map to its full statewide map extent. Use this tool if you want to move to another area of the state. Once the whole state appears on the screen, you can zoom in to the area you choose. Whenever you cannot orient yourself with the map on your screen (or your map pane is blank), click the "Zoom to the world" icon to restore a map of the entire state.
The Zoom In mode zooms in the map to the area bounded by a rectangle you drag. Click, hold, and drag a rectangle surrounding the area you want in your new view. When you release the mouse button, the screen redraws to explode the geography selected with your rectangle to fill the map pane. Alternatively, when in this mode a single click on the interactive map zooms in by a factor of 2 centered on the location of the click.
The Zoom Out mode zooms the map out to an area proportional to the rectangle. Click, hold, and drag a rectangle in the map pane. When you release the mouse button, the screen redraws to shrink the geography in the map pane to fit inside your rectangle; the smaller the rectangle, the larger the zoom out factor. Alternatively, when in this mode a single click on the interactive map zooms out by a factor of 2 centered on the location of the click.
Use the Pan mode to slide the map so you can see additional areas. Click, hold, and drag the map. When you release the mouse button, the map will refresh at its new map extent. When in Pan mode, you can use a mouse wheel to zoom in or zoom out.
Use the i-Tool mode to "drill down" through all Census layers and view detailed statistics for the layer and location you select. For more information, see Explore Census demographics.
The Measure mode will tell you the approximate length (in miles) of one or more linear segments. Click along the path you want to measure. When you double-click, District Builder will report the length of each segment and of the entire path.
The Legend tool shows the map legend in a separate browser window or tab. The legend describes map symbology, and it is particularly useful for interpreting "Value Ramp" color fill backgrounds.
The Print Map tool opens a Print Dialog for making a PDF map.
The Help Tool shows this Help manual in a separate browser window or tab.
The Google Maps tool launches Google Maps in a separate browser window or tab with approximately the same area and scale as your interactive map and with districts for your selected plan as a transparent fill overlay. Each district is listed twice: with a marker tied to the district number and with a checkbox for controlling visibility of the district's transparent fill. Either may be checked off to improve readability of the underlying Google base map.
The Locator tool is not in the toolbar, but rather along the right border of the interactive map near the bottom. Click the "+" icon to open the Locator inset.

The red box in the Locator inset indicates the portion of Florida shown in the interactive map. Drag the red box to reposition the interactive map. Click the "-" icon to close the Locator inset.

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Explore Census demographics

Use i-Tool mode to explore demographic details. When in i-Tool mode, clicking the map puts crosshairs at your selected location and opens a "Query Results" window. The first time you use i-Tool, the right panel of the "Query Results" window shows population counts and percentages for the district in which the crosshairs are located.

You can think of the crosshairs as "drilling down" through many layers of Census geography. In addition to being in a district, your crosshairs are in a county, a VTD, a Census block, a Census tract, and a Census block group. Your crosshairs also may be in a "place" (shorthand for municipality or Census designated place).

To visualize layers of Census geography in District Explorer's interactive map, check the ones you want to see under "Census Lines." Some Census lines do not appear until zoomed in sufficiently. Hint: Unchecking other Census Lines or Reference Lines will improve visibility of the layer(s) you want to see.

For each spot on the map, hundreds of Census statistics are available. In the left panel of the "Query Results" window, statistics are grouped by geography under three types of reports:

Selecting a category and geography in the left panel refreshes the grid in the right panel. What you select stays in effect until you make another choice. That is, if you click the map at another location (while in i-Tool mode), the grid refreshes with statistics for the new location.

Below are examples of using the i-Tool to view statistics for various geographies. In i-Tool mode, clicking east of County Road 1 and north of State Road 686 in Pinellas County puts a crosshairs marker at the selected location (see map inset in graphic below) and opens the Query Results dialog for "District Population (Census 2010 Redistricting Data)." The population counts and percentages shown in the grid are for the selected plan (in this example, the selected plan is FL2002_CON and the crosshairs are in Congressional District 10).

To view statistics for other layers, simply click on the geography of your choice in the left hand pane of the Query Results dialog. Click "County" to see which county intersects the crosshairs at your selected location and its population counts and percentages. The population counts and percentages shown in the grid are for Pinellas County.

Click "VTD" to see which voting tabulation district intersects the crosshairs at your selected location and its population counts and percentages. For the map inset below, Roads Reference Lines is checked OFF in the Layers Manager and VTD is checked ON (Roads Feature Labels is checked ON). Checking Census Lines ON helps with visualizing the geography associated with the statistics shown in the Query Results. Hint: Turning Roads Reference Lines OFF makes Census Lines easier to see.

Click "Block" to see which Census block intersects your selected location and its population counts and percentages.

Click "Place" to see which municipality (or Census designated place) intersects the crosshairs and its population counts and percentages. If your selected location does not happen to fall within a municipality or Census designated place, the Query Results will report, "There are no results for the Place layer at this point."

Clicking "District" under the Demographic category in the left panel yields an example of the much more detailed demographic profiles from Census Summary File 1 that are available for each of the following geographies: District, County, VTD, Block, Place (where applicable), Tract, and Block Group.

Click another location on the map to see the same statistics for the same layer of geography at a different location.

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Print current map view in PDF format

The Print Map tool opens a dialog for making a PDF map.

  1. Choose the orientation and scale for the map.
  2. Optional: Type a title and subtitle of your choice.
  3. Optional: Uncheck the "Map legend" box if you do NOT want the Legend to appear in the upper right hand corner of your map.
  4. After making your choices, click the "Make Map" button.
  5. The map opens in a separate window. Use the PDF toolbar's print button to print the map. Use the PDF toolbar's save button (diskette icon) to save the PDF to a file on your local computer.

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Computer Requirements

District Explorer requires the following:

Allow pop-ups in Internet Explorer:

Allow pop-ups in Firefox:

Allow pop-ups in Firefox 5:

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Frequently Asked Questions

Question: What are the differences between District Explorer and District Builder?

Answer: District Explorer and District Builder are companion web applications. Both are built with similar open source products. The navigation modes and other tools in District Explorer are similar to corresponding controls in District Builder. Both applications provide similar interactive access to detailed Census demographics. The main differences between the two are:

Question: How can I see statistics for the map I am viewing in District Explorer?

Answer: Statistical reports for current and proposed redistricting plans are published on the Florida Senate's Submitted Plans page. To access reports and downloads, go to the Plan Details page for the selected plan.

Question: Why are there no voter registration or election data in District Explorer?

Answer: It is common practice in most states, including Florida, to display such precinct data prominently on redistricting screens and reports. For example, partisan characteristics of precincts and districts typically are shown in multiple ways, including map shades of red and blue, detailed map queries, and continuously updated district performance estimates.

Recent changes to the Florida Constitution require that districts not be "drawn with the intent to favor or disfavor a political party or an incumbent." See Fla. Const. art. III, §§ 20(a) & 21(a).

With this new language, the mere presence of political metrics in the interface for building districts could create a perception, unsubstantiated and inaccurate though it may be, that partisan factors influenced how districts were drawn. The Senate, in an abundance of caution, therefore departed from traditional practice and chose to omit voter registration counts and election results from the dashboards in District Builder and District Explorer.

The Senate nevertheless will collect tabular precinct data required for Section 5 submissions to the United States Department of Justice and make them available on the Senate website. See 28 C.F.R. § 51.28.

Question: Why are there no geometric compactness measures in District Explorer?

Answer: Recent amendments to the State Constitution require districts "shall be compact." See Fla. Const. art. III, §§ 20(b) & 21(b). In different contexts compactness means different things, or a combination of things.

On one hand, some political scientists and mathematicians have employed abstract geometric calculations to evaluate districts according to their areas, perimeters, and similar geometric criteria. On the other hand, modern evaluations of compactness increasingly have looked at commerce, transportation, communication, and other practical measures that unite communities and promote the integrity and cohesiveness of each district for representational purposes. Such broader consideration shifts the focus from form to function and from shapes of districts to how actual communities relate to one another to form effective representational units.

Geometric measures tell how closely a district's shape matches one that is presumed to be compact, such as a circle or a rubber band perimeter (convex hull). Various algorithms have been proposed, and they yield conflicting and unsatisfactory results. Scholars caution that geometric measures are dependent on underlying geography and that their utility is not so much for evaluating a single district out of context, but rather for comparing complete alternative districting plans for the same jurisdiction. Geometric compactness scores, therefore, do not fit well among the dashboard statistics used to decide which areas should be added to or removed from districts. Voters and constituents do not need Reock, Convex Hull, Polsby-Popper and Schwartzberg scores to know what makes sense for creating compact districts in areas where they live.

District Explorer's Measure mode provides a handy way to determine the length and breadth of a district.

Question: Why do the Senate and House have different redistricting systems?

Answer: In July 2007, the Florida Senate started work on the next generation of redistricting software. Early on, the Senate determined that the best and most affordable technology for maximizing public participation would be open source web applications. In the summer of 2008, the Senate deployed the first version of its "District Browser" and "District Explorer" interactive map. It was launched from the Florida Senate's "Find Your Legislators" page. In November 2009, the Senate demonstrated for Executive Staff of the U.S. Census Bureau a District Builder prototype built on open source technology (MapServer/PostgreSQL/Apache). That same year, the Senate demonstrated the prototype at National Conference of State Legislatures meetings. The "alpha" version of District Builder (with 2001-2002 redistricting data) was used for NCSL redistricting simulation exercises in Providence, Rhode Island, and Washington, D.C.

The Florida House initiated a parallel effort to build its own web application for redistricting using Microsoft Azure/SQL Server/Bing Maps. The fact that the Senate and House systems are different is a plus. Each has unique features, and citizens can choose which better meets their needs. Some will choose the Senate's District Builder or District Explorer for their simple interface and layer controls, PDF maps, and statistics. Others will choose MyDistrictBuilder for its aerial maps and other features unique to the House solution. A few will use the two interchangeably, taking advantage of the strengths of both applications.

Full-featured redistricting systems typically cost thousands of dollars per user. The overarching goal shared by the Senate and House is giving the public free and easy access to the exact same software and data used by legislators and professional staff. It is remarkable that both the Senate and House succeeded, despite small budgets and considerable risks. With innovative technologies and joint public hearings, the Florida Legislature is promoting the most interactive and accessible redistricting ever.

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An area bounded on all sides by visible and/or invisible features shown on a map prepared by the U.S. Census Bureau. A block is the smallest geographic entity for which the Census Bureau tabulates decennial census data. The principle hierarchy of Census geography for Florida redistricting in 2011-2012 is County -> VTD -> Block. For the 2010 Census, 9,435 VTDs are nested within 67 counties, and 484,481 blocks are nested within VTDs.

Block Group

A statistical subdivision of a census tract consisting of contiguous census blocks. Block groups generally contain between 300 and 3,000 people. The block group is the lowest-level geographic entity for which the U.S. Census Bureau tabulates sample data from the American Community Survey. Florida has 11,442 block groups.

Census Geography

A collective term referring to the geographic entities used by the U.S. Census Bureau in its data collection and tabulation operations, including their relationships to one another.


The primary legal division of the state recognized by the U.S. Census Bureau. Florida has 67 counties.


Deviation for a district is the difference between the district's population and the "ideal" population. The "ideal" population is calculated by dividing the number of districts in a plan by the state population. The total deviation for a plan is the difference between the population of the district with the most population and the population of the district with the least population. Deviation may be measured as the number of people or as a percentage relative to the ideal population.


A district is a geographic area composed of contiguous Census geography that describes the territory, constituency, and voters represented by a Florida Senator, Florida State Representative, of U.S. Representative


An extent is the portion of the map that is visible in the map display. Panning changes the location, but not the scale of the extent, while zooming changes both the scale and location of the extent.

Geographic Hierarchy

The multiple nested hierarchies of Census geography are described on page 8 of the Census Bureau's Strength In Numbers guide. For the 2010 Census, 9,435 VTDs are nested within 67 Florida counties, and 484,481 blocks are nested within VTDs. This is the primary nested hierarchy used for Florida redistricting in 2010.

Ideal Population

The "Ideal Population" for a plan is calculated by dividing total state population by the number of districts in a plan. For example, dividing Florida's 2010 resident population (18,801,310) by 27, 40, and 120 nets ideal populations of 696345, 470033, and 156678 for congressional, senatorial, and state house districts, respectively.

Incorporated Place

A type of governmental unit, incorporated under state law as a city, town, borough, or village, generally to provide a wide array of specific governmental services for a concentration of people within legally prescribed boundaries.


See Incorporated Place


A concentration of population either legally bounded as an incorporated place, or delineated for statistical purposes as a census designated place.


A plan is a group of districts that contains all Census geography for the state of Florida. The Florida Constitution provides the division of the state into not less than 30 nor more than 40 consecutively numbered senatorial districts and not less than 80 nor more than 120 consecutively numbered representative districts of contiguous, overlapping or identical territory. The current number of Senate seats is 40. The current number of House seats is 120. The 2010 Census apportioned 27 representatives in the United States House of Representatives to the State of Florida.


A geographic entity established by local government for the purpose of assigning voters to polling places and conducting elections.

Public Plans

District Explorer users have access to all plans submitted for consideration by the Senate. The Florida Senate's Submitted Plans page is your portal for viewing current or proposed plans in District Explorer and for accessing statistical reports and downloads.


A small, relatively permanent statistical subdivision of a county, delineated for data presentation purposes by a local group of census data users or the geographic staff of a regional census center in accordance with U.S. Census Bureau guidelines. Originally designed to be relatively homogeneous units with respect to population characteristics, economic status, and living conditions at the time they are established, census tracts generally contain between 1,000 and 8,000 people. Census tract boundaries are delineated with the intention of being stable over many decades, so they generally follow relatively permanent visible features. However, they may follow governmental unit boundaries and other invisible features in some instances; the boundary of a state or county is always a census tract boundary. Florida has 4,245 tracts.

Unincorporated Area

Any geographic area that is not included in an incorporated place.

VTD (Voting Tabulation District)

VTDs are an official layer of Census geography based on political subdivisions submitted to the Census Bureau by supervisors of elections for the express purpose of fostering efficient administration of elections after redistricting. Florida has 9,435 VTDs.
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Standards for Drawing District Boundaries

Redistricting plans enacted by the Legislature must comply with all requirements of the United States Constitution, the Voting Rights Act of 1965, the Florida Constitution, and applicable federal and state court cases. Professional staff of the Florida Senate Committee on Reapportionment prepared a check list of redistricting standards for the narrow purpose of providing Senators and citizens a basic introduction to applicable legal requirements. The check list should not be construed as legal advice. For assistance interpreting redistricting standards, consult an attorney.

☑ Plan is complete.

The plan must have the required number of districts and no unassigned areas (or holes). A plan with fewer than the required number of districts cannot be enacted, but it may be an effective way to show what you think works for your community. Citizens may submit plans that have only a small number of districts in the region with which they are familiar.

☑ All districts are contiguous.

See Fla. Const. art. III, § 16(a). See also, Fla. Const. art. III, §§ 20(a) & 21(a). A district is contiguous if no part of the district is isolated from the rest of the district by another district. See In re Apportionment Law, Senate Joint Resolution 1E, 414 So.2d 1040, 1051 (Fla. 1982). A district lacks contiguity when its parts "touch only at a common corner or right angle." Id. The Florida Supreme Court also has ruled that land and water territories both count for achieving contiguity. See In re Constitutionality of Senate Joint Resolution 2G, 597 So.2d 276 (Fla. 1992).

Dry Tortugas National Park in Monroe County (67 miles west of Key West) is a special case. In Census TIGER geography, Dry Tortugas National Park is disconnected from the contiguous lands and waters making up the rest of Florida (including the Marquesas Keys 18 miles west of Key West). Therefore, whatever district includes Dry Tortugas National Park will have two parts. This special case is NOT considered to violate the contiguity standard.

☑ Districts are consecutively numbered.

See Fla. Const. art. III, § 16(a). This means, for example, that a 40-district senatorial plan must have districts labeled with each of the numbers between 1 and 40. It does not mean adjoining districts must be consecutively numbered. That is, there is no requirement that district 2 touch either district 1 or district 3. See In re Apportionment Law, Senate Joint Resolution 1E, 414 So.2d 1040, 1051 (Fla. 1982). District Explorer labels each district in your plan from a series of consecutive numbers. Based on Florida Supreme Court precedent, your plan will violate the consecutive numbering requirement only if you skip a number.

☑ Districts are equal in population.

See Fla. Const. art. III, §§ 20(b) & 21(b). Dashboard Statistics and Plan Statistics show district deviations from the ideal (target) population. The "one person, one vote" requirement set forth by the United States Supreme Court means that congressional districts must be mathematically equal, unless small variances are necessary to achieve some legitimate, consistently applied state objective. See Karcher v. Daggett, 462 U.S. 725 (1983). On the other hand, legislative districts need not achieve precise mathematical equality, but only substantial equality, if deviations are based on some rational state policy. See Reynolds v. Sims, 377 US 533 (1964). An overall range of less than 10 percent is constitutional in the case of state legislative districts, absent proof of arbitrariness or discrimination. See Cox v. Larios, 542 U.S. 947 (2004). "Overall range" and "total deviation" both mean the same thing:

☑ The plan adheres to the Voting Rights Act.

Under Section 5 of the Voting Rights Act, there can be no "retrogression," or worsening in the position of racial minorities, with respect to the effective exercise of the right to vote in any jurisdiction covered by the Act. In Florida, the covered jurisdictions are Collier, Hardee, Hendry, Hillsborough, and Monroe counties. More information is available on the United States Department of Justice Section 5 web page.

Additionally Section 2 of the Voting Rights Act may require drawing districts which contain a majority minority population if three threshold conditions are present: 1) a minority group is large enough and lives closely enough together so that a relatively compact district in which the group constitutes a majority can be drawn, 2) the minority group has a history of political cohesiveness, and 3) the white majority has a history of voting as a group so that it usually defeats the minority group's preferred candidate. The totality of circumstances, including a past history of discrimination that continues to affect the exercise of a minority group's right to vote, must then be taken into consideration to determine whether the minority group has less opportunity than other members of the electorate to participate in the political process and elect representatives of its choice. See Thornburg v. Gingles, 478 U.S. 30 (1986). More information is available on the United States Department of Justice Section 2 web page. The United States Department of Justice also publishes the full text of the Voting Rights Act of 1965 and amendments.

☑ Race considerations do not impermissibly dominate process of drawing the plan.

Race may be a factor in drawing districts, but not the predominant factor. See Shaw v. Reno, 509 U.S. 630 (1993). If traditional, race-neutral principles are subordinated to race, the district plan will be subject to strict scrutiny and may be overturned unless it is narrowly tailored to further a compelling interest. See Miller v. Johnson, 515 U.S. 900 (1995). Two compelling interests have been recognized or assumed to be valid: eradication of the effects of specific, identifiable racial discrimination and compliance with the Voting Rights Act. See Shaw v. Hunt, 517 U.S. 899 (1996).

☑ Districts are not drawn with the intent or result of denying or abridging the equal opportunity of racial or language minorities to participate in the political process or to diminish their ability to elect representatives of their choice.

See Fla. Const. art. III, §§ 20(a) & 21(a). In recent decades, the Legislature has enhanced minority opportunities substantially through redistricting. These standards ensure that the Legislature's traditional power to maintain and even increase minority opportunities is not impaired or diminished by other, potentially conflicting standards an Amendments 5 and 6. The Legislature may continue to apply all of the same methods to preserve and enhance minority representation as it has applied with so much success in recent decades. Amendments 5 and 6 expressly place these voting-rights protections above standards such as compactness and adherence to political and geographical boundaries.

For more information about the Legislature's non-retrogressive interpretation of potentially conflicting provisions in Amendments 5 and 6, see Submission of Amendments 5 & 6 to the United States Department of Justice under Section 5 of the Voting Rights Act, pp. 7-9 (March 29, 2011).

☑ Districts are not drawn with the intent of favoring or disfavoring a political party or incumbent.

See Fla. Const. art. III, §§ 20(a) & 21(a). Choices to include or exclude areas from a district based predominantly on partisan or incumbency considerations violate the State Constitution. Choices to include or exclude areas based on factors unrelated to party and incumbency do not, even if they happen to have political effects.

☑ Districts are compact.

See Fla. Const. art. III, §§ 20(b) & 21(b). The various measures of compactness that courts in other states have utilized include mathematical calculations that compare districts according to their areas, perimeters, and similar geometric criteria, and broader considerations of how actual communities relate to one another to form effective representational units. Thus, geometric compactness looks exclusively at the shapes of particular districts, while functional compactness looks to commerce, transportation, communication, and other practical measures that unite communities and promote the integrity and cohesiveness of each district for representational purposes. A district need not be compact if its compactness would cause a conflict with any of the standards outlined above.

☑ Districts utilize political and geographical boundaries, where feasible.

See Fla. Const. art. III, §§ 20(b) & 21(b). Where feasible, districts must be drawn with respect to political and geographical boundaries. To achieve other redistricting standards, however, including population equality and the protection of racial and language minorities, districts may depart from political and geographical boundaries.

Obviously, it is not feasible for a single plan to follow all existing political and geographical boundaries. Some political boundaries may not be suited to the achievement of equal and effective representation in the State Legislature and Congress. Many municipalities are not compact, and their boundaries are subject to frequent change.

An important purpose of joint public hearings in summer 2011 is to gather citizen input about which boundaries matter for forming effective representational units.

Census Geography

A helpful booklet describes population and geographic products the United States Census Bureau produces specifically for apportionment and redistricting. See Strength In Numbers 2010.

In District Builder, county/VTD/block is the primary hierarchy of Census geography. For the 2010 Census, 9,435 VTDs are nested within Florida's 67 counties, and 484,481 blocks are nested within VTDs.

In Florida, Census voting tabulation districts (VTDs) for the 2010 Census were delineated in partnership with supervisors of elections for the express purpose of easing administration of future elections. Where district boundaries follow VTD geography, it significantly will ease implementation of new districts. Census blocks are the smallest units of geography for which population figures are tabulated.

Census tracts, block groups, and places (municipalities and census designated places) also are available in District Explorer for modeling districts. Where such geographies are used in lieu of VTDs and their boundaries do not conform, implementing new districts quickly, as required for elections in fall 2012, will be complicated.

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License Information

District Explorer was built with the open source products listed below.

Software or DataLicense TypeLinkFile
PHP MapscriptN/A
Apache Web ServerApache
Apache AntApache
PHPPHP License v3.01
FPDF (PHP Pdf creation library)Not sure, but the website says:"FPDF is released under a permissive license: there is no usage restriction. You may embed it freely in your application (commercial or not), with or without modifications. "
Map rendering fontsGPL, see attached, LiberationSans-Italic.ttf, LiberationSans-BoldItalic.ttf, LiberationSans-Regular.ttf
Map rendering fontsSee Bitstream Vera Fonts Copyright in page,VeraBd.ttf, VeraMoBI.ttf,VeraMoIt.ttf,VeraSe.ttf, VeraBI.ttf,VeraIt.ttf, VeraMoBd.ttf, VeraMono.ttf, VeraSeBd.ttf
PythonPython license
Mozilla FirefoxN/A
Nullsoft Scriptable Install Systemzlib/libpng for NSIS bzip2 license for compression
Sun JavaGPL/JCP>
jEditGPL v2
ka-MapN/A, grabbing.cur, grab.cur
Silk Icons from FAMFAMFAMCCA 2.5 (requires us to give attribution), map_edit.png, lock_open.png, lock_closed.png (modified), info.png (org named information.png)
chameleonChameleon License (see attached) (save icon),Icon_cancel.png (abandon icon), Icon_update.png (refresh), Icon_search.png(find),Icon_zoomfull.png(full extent),Icon_zoomin.png(zoom in),Icon_zoomout.png (zoom out),Icon_pan.png (pan),Icon_ruler.png (measure),icon_query.png (I tool),button_copy_1.png(copy/paste district),icon_roi_clear.png (erase lasso),icon_roi_undo.png(redo),icon_roi_redo.png(undo) modified from icon_roi_redo.png, icon_roi_polygon.png (assign by poly),Icon_add_point.png (assign by point),Icon_last.png(last extent) modified from icon_demote.png,Icon_next.png(next extent) modified from icon_demote.png
Itasca map server demoN/A since this is distributed with MS4W (or I think it has been in the past, it should fall under the ms4w license,ushwy.png
DOT road dataFlorida public records, toll roads, US highways, state roads, and county roads shapefiles
Open space dataFlorida public records managed area shapefile
Census dataUS public records TIGER/Line shapefiles, 2010 Redistricting data progam MAF/TIGER shapefiles, PL94-171 census counts data

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