Requisites for the use of GIS software for redistricting can be divided into the following three categories: computer systems and software, spatial and other data, and users. In addition, a general understanding of GIS and the potential advantages and disadvantages of its use, as well as a frame of reference that permits its use, are important considerations in adopting GIS for redistricting.
Computer Systems and Software
GIS software runs on the whole spectrum of computer systems ranging from portable personal computers (PCs) to multi-user supercomputers. Regardless of what hardware system is chosen, a number of elements must be considered for the GIS software to operate effectively:
- The computer must have a processor with sufficient power to run the software and sufficient memory for the storage of large volumes of data.
- A high resolution colour graphics screen is necessary to view the output.
- Data output devices such as printers and plotters (as well as data input devices such as digitisers and scanners if paper data must be transformed into electronic data) will have to be acquired.
Hardware requirements are both dependent on and determining of software requirements; hardware limitations may mean that particular software products cannot be utilised, while the availability of software can dictate what sorts of hardware must be purchased.
Software refers to both the operating system and specific application packages. For GIS this is usually UNIX or Windows NT operating systems along with GIS software programs such as Arc/Info, Intergraph, MapInfo or Maptitude or customised GIS software packages for redistricting.
A key factor that often dictates the choice of hardware and software is cost: budgetary constraints, especially in many developing countries, will serve to limit the choice of which computer system and software can be used.
Data
Data includes both the cartographic database needed for using GIS applications as well as any accompanying attribute data (primarily population data in the case of redistricting). Data availability and accuracy - and especially the availability of digital cartographic data - are some of the most important requisites for the development of GIS capabilities. The extent of GIS diffusion is often dictated by the availability of digital cartographic data, or more often, the willingness to dedicate resources to creating such a database.
As discussed in the case study, the U.S. Census Bureau has produced a complete set of uniform, digitised maps covering the entire country. See; Case Study: The Use of GIS Software for Redistricting in the U.S. during the 1990s. A number of other countries have also developed, or are well on their way to developing a uniform, digitised set of maps for their country. On the other hand, many countries have only begun - or have not yet begun - this process. For example, as a result of the extremely large size of the area, the changing nature of the boundaries, a history of secrecy and the lack of data standardisation, many of the newly formed countries of the former Soviet Union have not developed national cartographic databases.
The availability of electronic data, and hence the GIS market, is particularly well-developed in North America, with Australia and New Zealand following closely behind. The European GIS market is highly fragmented, with little agreement on common mapping standards and considerable differences in the professional cultures that are involved in GIS applications. Generally the north and west European countries have experienced higher levels of GIS penetration than those of southern and eastern Europe. However, there are also marked variations within specific countries in Europe as well.
The level of GIS diffusion in developing counties is generally much lower. Developing countries are faced with a number of limitations which revolve around the linked issues of cost, training of personnel, and data availability. In addition, because of the lack of transfer of technology to many developing countries, relatively little awareness of GIS and its uses exists in these countries.
While some traditional democracies see GIS as helping unravel problems about gerrymandering, attaining uniformity in district populations and constructing communities of interest, these issues are currently not a high priority in most newly emerging democracies or developing countries. However, such high priority issues in developing countries and newly emerging democracies as resolving urban and rural land use, transportation, housing, and environmental pollution can benefit from the use of GIS, so this technology may be adopted by these countries in the relatively near future - at which point, of course, GIS technology and computerised maps may also be adapted for use in redistricting.
Users
Users refers to trained personnel able to operate the GIS system. The main requisite for users of GIS is a familiarity with basic GIS software and systems, but some general geographic and cartographic knowledge, as well as general computer competence, is also necessary in order to use GIS software for redistricting.
Many GIS packages are difficult to use without proper training. The language barrier may pose an additional problem as many GIS manuals and programs - especially those designed specifically for redistricting - are written only in English.
The requisites for GIS use are rather uniform. The degree to which countries meet these requisites, however, varies widely - and thus, so does the degree to which countries have utilised GIS technology.
