This final section introduces some of the basic concepts associated with what has become known as spatial data infrastructure, the set of techniques, institutions, standards, and other arrangements that facilitate the exchange of spatial data and tools, and in this way support spatial analysis. Until the 1980s it was generally accepted that responsibility for the acquisition and dissemination of spatial data lay with national mapping agencies, who produced topographic maps and other information at public expense. This system began to fall apart around 1990, however, for a number of reasons. Governments were less and less willing to foot the steadily increasing bill; 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 commercial sector was pushing for new markets for its products, arguing that subsidised government production of spatial data constituted unfair competition. 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.