This final section introduces some of the basic concepts associated with what has become known as spatial data infrastructure, the set of representations created using recognized standards and other arrangements that provide sources of spatial data and tools, in ways that support spatial analysis. Spatial data infrastructures provide some of the raw ingredients to spatial analysis, as well as a framework for the display of results that enable ready interpretation by users.
Until the 1980s it was generally accepted that responsibility for the acquisition and dissemination of spatial data lay with national mapping agencies, which produced topographic maps and other information at public expense. Parts of this system began to degrade and decentralize around 1990, however, for a number of reasons. On the one hand, governments became less and less willing to foot the steadily increasing bill; particularly as new technologies created demands for increasingly high value information products. One the other hand, some of the same developments in computing technology and GPS had made it possible for virtually anyone to become a creator of spatial data at low cost; and the ‘creative commons of the Internet allowed the creation of spatial data infrastructures by communities of volunteers. For example, Figure 2‑13 shows the results of calculating a school catchment area and an analysis of pupil educational attainment in and around the area, mapped against a backcloth of data from Open Streemap (www.openstreetmap.org). Related to this second trend has been the commercial sector lobby for new markets for its products, arguing that subsidized government production of spatial data constituted unfair competition. The movement of the search engines of Google and Microsoft into Internet mapping has resulted in spatial data infrastructures becoming available to any non commercial user at zero cost, on the presumption that the supply of such data can be funded through an advertising driven business model. Today, many countries now have extensive spatial data infrastructures, and responsibility for the acquisition and dissemination of spatial data is now shared between numerous agencies, companies, and individuals.