The term ‘GIS’ is widely attributed to Roger Tomlinson and colleagues, who used it in 1963 to describe their activities in building a digital natural resource inventory system for Canada — Tomlinson (1967, 1970). The history of the field has been charted in an edited volume by Foresman (1998) containing contributions by many of its early protagonists. A timeline of many of the formative influences upon the field is available via the CASA website: www.casa.ucl.ac.uk/gistimeline/; a printed summary is provided by Longley et al. (2005, pp 19-21), and useful background information may be found at the GIS History Project web site based at the NCGIA (Buffalo): http://www.ncgia.buffalo.edu/gishist/. Each of these sources makes the unassailable point that the success of GIS as an area of activity has fundamentally been driven by the success of its applications in solving real world problems.

Figure 3‑1 is a simplified illustration of the way in which today’s GIS is configured, in terms of physical and human resources. Innovations in hardware diffuse rapidly, and the physical configuration of a system at any particular point in time will be a function of recent and past investment decisions. The software tools that characterise a GIS are similarly likely to be a function of budget considerations and the availability of suitable toolsets. Networking, both local- and wide-area, is essential to the functioning of a GIS.

The near universal availability of the Internet in developed countries, the use of websites to showcase products and services, and the popularity of downloads as a means of acquisition make the wide-area network key to the acquisition of data and software tools often identified using search engines. However, ubiquity of Internet connections and search engines is not alone sufficient to successful GIS application. In the case of data, it is necessary to establish the provenance of the different data options that are available, by reference to the metadata that should accompany each of them.

In the case of software tools, the sometimes vast choices that are presented as the result of Internet searches rarely establish fitness for particular purposes, or identify the most cost-effective option for a particular application. This highlights an important difference between data and software: while the veracity of metadata can often be checked (e.g. with respect to other datasets, or sometimes through direct field measurement in the real world), there are no such safeguards available for most software tools. Commercial software is very rarely ‘open source’, for a range of reasons including protecting copyright and maintaining user support. Even ‘public domain’ software is often not open source. Thus, although the Internet makes it possible to assemble information about software, Internet searches do not necessarily enable objective comparison of software functions. One of the important contributions of the present Guide is to raise awareness of the range of software options that are available and the quality of the results that may be produced. In this way we hope to assist the people that use GIS, and to help users to develop improved procedures for undertaking spatial analysis.

Our primary concern is with developing adequate understanding of the ways in which computer software can be used to solve geographical problems. Some of this software has its roots in particular applications sectors and the technological setting in which it was developed, but these distinctions are blurring with time. The field of spatial analysis has a rich and multidisciplinary history, extending back well before the advent of cheap, high performance computing. Today, however, it is the suites of software commonly described as ‘Geographic Information Systems’ (GIS) that provide the computer environment for much spatial analysis research and practice.

Updates and developments in hardware and networking are widely discussed in much of the GIS trade press (see, for example, the “Other GIS web sites” links at the end of this Guide). The people requirements of GIS and the way that the GIS industry meets them are considered in Longley et al. (2005, pp 24-31). The importance of people and procedures are usually specific to the context in which an application is developed and define the organisational setting to GIS. This has received quite wide attention in the literature — e.g. Bernhardsen (2002); Masser et al. (1996). The issues of GIS data hold an intermediate position, in that classes of applications share some very common data problems, yet these can be alleviated or accentuated by the particular context in which GIS analysis is performed. At the end of the day, any GIS application can only be as good as the data that are used to create it and its relevance to the organisation that commissioned it. Thus the relationship between data issues and the organisational setting in which people and procedures operate will be core to much of our discussion of a range of techniques and representative applications areas.

There are some caveats to this heavy emphasis upon the importance of context in GIS analysis. The wide availability of low cost Global Positioning System (GPS) receivers means that primary data relating to physical features can be collected wherever uninterrupted signals can be received to standards that are generally understood. Yet many GIS applications build upon the legacy of spatial data that have previously been collected, and there is considerable variability in the amount, relevance and quality of secondary data that can be assembled for different parts of the world.

Chapter 2 described the established scientific elements that govern ‘typical’ GIS applications. In practice, applications are likely to be governed by the organisational practices and procedures that prevail with respect to particular places (Section 2.2.1). Not only are there wide differences in the volume and remit of data that the public sector collects about population characteristics in different parts of the world, but there are differences in the ways in which data are collected, assembled and disseminated (e.g. general purpose censuses versus statistical modelling of social surveys, property registers and tax payments). There are also differences in the ways in which different data holdings can legally be merged and the purposes for which data may be used — particularly with regard to health and law enforcement data. Finally, there are geographical differences in the cost of geographically referenced data. Some organisations, such as the US Geological Survey, are bound by statute to limit charges for data to sundry costs such as media used for delivering data while others, such as most national mapping organisations in Europe, are required to exact much heavier charges in order to recoup much or all of the cost of data creation. Analysts may already be aware of these contextual considerations through local knowledge, and other considerations may become apparent through browsing metadata catalogues. GIS applications must by definition be sensitive to context, since they represent unique locations on the Earth’s surface.

A goal of this Guide is to focus in greater detail upon the characteristics of data and how they support particular applications in particular organisational settings. We illustrate this here by using a wide range of examples from datasets that come from all parts of the world. However, in addition we have made a separate series of Case Studies accessible via the web site www.spatialanalysisonline.com, initially using London as our ‘applications laboratory’. We are not seeking to present a ‘London centric’ view of the world ― rather, through selected case studies, to illustrate how different applications fields have developed.