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Redistricting Resources and Operations

This section summarizes resources available for redistricting that make use of Census 2000 geographic and demographic data resources. Access to and use of these resources are described in the context of redistricting operations consistent with today's technological alternatives.

Today one person can do what perhaps a team of 10 people would be required to do for a similar redistricting application following the 1990 census. Possibly more significant is the ability to convey alternative plans to a wider set of stakeholders, more easily and less expensively, through the Internet -- a capability which has grown almost infinitely.

The Constitutionally mandated reason for the decennial census is for Congressional reapportionment and the closely associated redistricting process. Census 2000 geographic and demographic data resources for use in reapportionment and redistricting are described in the Census 2000 Data Access and Use web site.

Decennial census data are widely used in other types of districting applications. Local and state governments must redraw boundaries to reflect changes in population size and composition. Redistricting applications include redistricting state legislatures, other types of statewide geographic area redistrictings, regional management areas, sales territories, school districts (attendance areas and election areas), fire districts, police beats, city election districts, and other types of geography.

Role of GIS. Advancements in Geographic Information Systems (GIS) offer new, faster, less expensive, and [potentially] more accurate means of completing a successful redistricting operation. Advancements in Internet-related technologies make it inexpensively and readily achievable to make the results of multiple proposed plans available for viewing with a Web browser. As a result, more stakeholders have a better opportunity to review the scope of proposed alternative plans. Finally, the results of the plans remain something of a living resource--the GIS can be restarted at any time, if the components are all retained and documented, and revisions can be made without starting over with paper-sourced materials.

Redistricting Solutions. Resources listed below can help you implement effective redistricting solutions.

  • Review and monitor the unique Census 2000 Data Access and Use Website to learn about existing geographic and demographic data developments and keep up-to-date on relevant new data resources and application issues. For example, here you can learn about new Census 2000 census block level data from Summary File 1, what level of subject detail is available. how to access the data, and find related sources of reference and data user information.
  • Attend the Geodemographics Data Integration and Analysis computer-based hands-on training sessions to learn how to use software and data resources. If necessary, consider a custom session focused on your redistricting needs to meet your specific needs.
  • Download free Census 2000 geographic and demographic data resources that can be "plugged directly into" the redistricting processes. For example, you can download Census 2000 county by census block map files (and many other popular geographic layers) in shape file format for your free unlimited use.
  • Use the ASC2DBF software to convert no-cost downloaded ASCII Census 2000 data from the Census Bureau web server into dbase structure.
  • Use the Cen2Shp software to automatically integrate the Census 2000 demographic data into map files in shape file format.
  • Explore web-accessible interactive maps with the Integrated Geodemographic Mapping System to see how alternative plans can be made available on the Web. This type of facility enables any stakeholder with a web browser to access and compare alternative plans.
  • Contact Proximity for assistance with the collective process of redistricting. We can help develop basic specialized geographic concordance data files needed for the redistricting process, assist in setting redistricting determinant factors and acceptable deviations between districts, and even and provide all provide the integrated set of PC-based redistricting data files and software, prepare a base plan, support the collective process of developing alternative plans, and facilitate or directly implement web-based browser access to redistricting plans through use of Internet freeware, open architecture, mapserver operation.

Standalone PC Redistricting. To perform redistricting in a standalone PC environment, requires these elements:

  • Map boundary files that contain the small area geographic unit building block geography (census blocks?) for the area to be redistricted.
  • A cross-reference file that associates each of the unit building blocks in the map files to an initial district within the area to be redistricted (a file version of a base/starting point plan).
  • The demographic data that will be used as the basis for redrawing the districts in the properly structured file covered the area to be redistricted.
  • An understanding of the demographic subject matter factors and how acceptable deviations from district to district will be defined/applied.
  • PC mapping software.
  • Personnel who can develop, integrate, and operate these components.

One alternative for the PC mapping software used by Proximity is the ArcView mapping software augmented with the districting extension. The districting extension enables ArcView to be used to recognize groupings of smaller geographic areas, such as census blocks and census tracts, into a set of larger district areas. Using ArcView with this extension enables the user to view, modify, save and output characteristics of a redistricting plan.

The key to successful use of any mapping software to develop district plans extension involves 1) understanding how to establish the base data that convey the "starting point" for the plan and 2) how to define parameters and deviations acceptable in the redistricting process, and 3) acquiring and making the data components available in the required formats and locations.

PC mapping software can then help create a plan and alternative plans. The mapping software helps you create and view a plan, manipulate and assign district elements (e.g. census blocks), and dynamically recalculate statistical measures for the districts.

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