The Dictionary of Human Geography (78 page)

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Authors: Michael Watts

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Geographic Information Systems (GIS)
In (NEW PARAGRAPH) the simplest terms, GIS (or GISystems) is the mix of hardware, software and practices used to run spatiaL anaLysis and mapping programs. GIS does not refer to a homoge neous entity, nor one machine or a single prac tice but to a collection of practices, software and hardware with the ability to collect, store, display, analyse and print information about the Earth?s surface (or any other scale of geog raphical data). Each such system is able to capture, store, check, integrate, analyse and display spatially referenced data about aspects of the earth. GIS allows the combination of geographical data sets (or layers) and the creation of new geospatial data to which one can apply standard spatial analysis tools. Comprehensive GIS require a means of: (i) data input, from maps, aerial photos, satellites, surveys and other sources (cf. remote sens ing); (ii) data storage, retrieval, and query; (NEW PARAGRAPH) data transformation, analysis and model ling, including spatial statistics; and finally (NEW PARAGRAPH) data reporting, such as maps, reports and plans. (NEW PARAGRAPH) The GIS acronym has tended to focus on the software developed by specific corpor ations with less attention to the spatial data that are the basis for knowledge generation. Geographical information is information about where something is or what is at a certain location. For example, we may have data from a forest on where some of the few remaining spotted owls live which is geographical information. What trees grow in the areas inhabited by the owls is also geographical in formation, because it has a spatial component. Spatial data are any data that have a location that can be geocoded. Increasingly, data from most domains include spatial data. (NEW PARAGRAPH) GIS are uniquely integrative. Where spatial data are available, GIS can offer a range of functionality. Whereas other technologies might be used only to analyse aerial photo graphs and satellite images, to create statistical models or to draft maps, these capabilities are all offered together within a comprehensive GIS. With its array of functions, GIS should be viewed as a process rather than as merely software or hardware. To see GIS as merely a software or hardware system is to miss the crucial role it can play in a comprehensive decision making process. (NEW PARAGRAPH) GIS has different uses and meanings among a range of users. Municipalities, for instance, view GIS as the software that allows planners to identify residential, industrial and commer cial zones and store tax information. It maps the exact location and survey coordinates of each taxable property, and provides answers to queries such as: ?How many properties would be affected by the addition of an extra lane to Highway 1 between 170th and 194th Streets?' Population heaLth researchers, on the other hand, may use GIS to define the boundaries of communities that enjoy varying health out comes. In this instance, GIS is not a piece of software, but a scientific approach to the prob lem: ?How do we define crisp boundaries to demarcate fuzzy and changeable phenomena?' (cf. fuzzy sets). The latter is a fundamentally philosophical issue that must be resolved through computing and its answer lies some where between GIS and the underlying theory of geographic information science. These two types of users have different goals and experiences of GIS. One is interested in ?where' spatial entities are or might be, while the other is concerned with ?how? we encode spatial entities (e.g. communities, urban/rural areas, forests, roads, bridges and anything that might appear on a map), and the repercus sions of different methods of analysis on answers to geographical questions. The diver sity of GIS use is rooted in its history. (NEW PARAGRAPH) The development of GIS began in the 1960s, when the technology and epistemoL ogy that underlie it were first being developed. Methods of computerizing cartographic pro cedures were coincident with the realization that mapping could segue neatly into analysis. In 1962, Ian Harg, a landscape architect, introduced the method of ?overlay' that was later to become the defining methodoLogy of GIS. He was searching for the optimal route for a new highway that would be associ ated with suburban development. His goal was to route the highway such that its path would involve the least disruption of other ?layers' of the Landscape, including forest cover, pastoral valleys and existing semi rural housing. He took multiple pieces of tracing paper, one representing each layer, and laid them over each other on a light table. By visually exam ining their intersections, he was able to ?see' the only logical route. Ironically, none of McHarg's initial analysis was done using a computer. The metaphor of overlay was, however, integrated into early GIS, and be came the basis for a range of analytical tech niques broadly known as ?spatial analysis'. (NEW PARAGRAPH) spatiaL anaLysis is differentiated from ?mapping' because it generates more informa tion or knowledge than can be gleaned from maps or data alone. It is a synergistic means of extracting information from spatial data. In the early development stages of GIS, however, few people recognized the power of analysis, and the technology was generically referred to as ?computerized cartography'. As such, GIS was unimpressive. Early computerized maps were very primitive compared to the exquisite maps produced through manual carto graphy. This comparison led to reluctance among geographers to adopt GIS as a ?substi tute' for traditional cartography. (NEW PARAGRAPH) The questionable aesthetic merit of tradi tional maps was, however, a detraction from the power of computerized spatial analysis. That power was first explored in universities in the late 1950s and early 1960s. Influenced by the Quantitative revoLution and the development of computers, researchers began to develop tools that could be used to analyse and display spatial data though not always in map form. One of the earliest computer cartog raphy systems was developed in Canada, the brainchild of Roger Tomlinson and Lee Pratt. Tomlinson had been using aerial photography to map forest cover in order to recommend locations for new growth; Pratt worked for the Canadian Ministry of Agriculture, which wanted to compile land use maps for the entire country, maps that would describe multiple characteristics including agriculture, for estry, wildlife, recreation areas and census di visions. Tomlinson suggested that they pioneer a computerized system in which land use zones were digitally encoded so that they could be overlaid with other relevant layers such as urban/rural areas, soil type and geology. This happenstance meetingled, in 1964, to the Can ada Geographical Information System (CGIS). The name of the system was bestowed by a member of the Canadian Parliament. (NEW PARAGRAPH) There were parallel developments in Europe. Tom Waugh, for example, developed an early GIS system with the acronym GIMMS. It was a vector based GIS system with sophisticated analysis, and was eventually used in twenty three countries (Rhind, 1998). GIMMS preceded ESRI (see below) in devel oping a commercial GIS and was relatively sophisticated for the 1970s and 1980s includ ing cartographic options and batch processing. In the USA, the Harvard Graphics Laboratory was a tinderbox of the GIS revolution. Re search at the laboratory established an efficient method for computerized overlay using poly gon (vector) boundaries. The laboratory was populated by a host of researchers who had a profound influence on the development of cur rent GIS, including Nicholas Chrisman and Tom Poiker. A diaspora of researchers from the Harvard Laboratory in the 1970s contrib uted to the dissemination of GIS, especially into the private sector. Scott Morehouse, a junior member, left in 1981 to work for a company in California called Environmental Systems Re search Institute (ESRI), where he re developed the algorithm for vector overlay which became a cornerstone of the program ARC/INFO. This dispersion of ideas from the Harvard Laboratory was the beginning of one GIS identity: that linked to software packages, hardware systems and technology in general (Chrisman, 1988). (NEW PARAGRAPH) Institutional and governmental support for GIS was also a major impetus for its growth and adoption from the 1970s onward. In the UK, four multidisciplinary Regional Research Laboratories (RRLs) were designated by the Economic and Social Research Council. They were designed to facilitate primary functions of GIS, including spatial data management, software development, spatial analysis and training of GIS researchers (Masser, 1988). In the USA, the National Center for Geographic (NEW PARAGRAPH) Information Analysis was funded by the National Science Foundation (NSF). Three US universities with GIS expertise were chosen as primary research centres. Their role was to facilitate understanding and imple mentation of geospatial methodologies and develop university adoption of these tech niques. The NCGIA also played an important role in hosting and responding to epistemo LogicaL and pragmatic critiques of the tech nology (Pickles, 1995b; Curry, 1998). (NEW PARAGRAPH) The development of GIS, however, is not rooted solely in computer laboratories and universities in the latter part of the twentieth century. It is also an outgrowth of attempts to automate calculation in the nineteenth cen tury reflected in efforts, for example, to code population data for the US census in 1890 (Foresman, 1998). Pre eminent GIS scholar Michael Goodchild makes the point that GIS was developed during a period when informa tion was increasingly being translated into digital terms and disseminated widely (Good child, 1995). If geographers had not explored the possibilities of digital manipulation of spa tial data, other disciplines would have initiated the process. As it is, many roots of GIS are in disciplines other than geography including landscape architecture and surveying. Like all technologies, GIS is an outcome of both social and technological developments. ns (NEW PARAGRAPH) Suggested reading (NEW PARAGRAPH) DeMers (2000); Longley, Goodchild, Maguire and Rhind (1999); Schuurman (2004). (NEW PARAGRAPH)
geographical analysis machine (GAM)
An (NEW PARAGRAPH) example of automated spatial data analysis catalysed by three factors: the growing avail ability of digital data with point (x,y) geo coDing; a move from statistical techniques ?smoothing over? geographical variation to LocaL statistics revealing geographical pat terns in data; and increased computational power to guide where to look. GAM passes a moving window of fixed radius (or population count) across a study region, repeatedly test ing for unusual clusters of a particular feature. Successfully used to study the clustering of cancers, GAM and its primary architect Stan Openshaw inspired much of the research in geocomputation. rh (NEW PARAGRAPH) Suggested reading (NEW PARAGRAPH) Openshaw (1998). (NEW PARAGRAPH)
geographical explanation machine (GEM)
(NEW PARAGRAPH) Whilst the geographicaL anaLysis machine (NEW PARAGRAPH) discovers spatial patterns in geographical data sets, the geographical explanation machine tries to ?explain? them by identifying predictor variables with a spatial distribution matching the patterns found. As a tool for computer assisted learning, GEM is pioneering. The problem, however, is that looking hard enough through sufficient data sets as a computer can will probably reveal an association al though not necessarily one with scientific or rational meaning. Many geographers will baulk at an approach to social scientific explanation that is so avowedly empiricist and not guided by theory. Perhaps the ?E? in GEM could bet ter be described as exploration. rh (NEW PARAGRAPH) Suggested reading (NEW PARAGRAPH) Openshaw (1998). (NEW PARAGRAPH)
geographical imaginary
A taken for granted spatial ordering of the world. ?Imaginary? is a concept derived from psycho anaLytic theory, in particular the work of Jacques Lacan and Cornelius Castoriadis, and in its original versions it implied a sort of primitive or ur geography: ?The imaginary is the subject?s whole creation of a world for itself? (Castoriadis, 1997; cf. Gregory, 1997a). In human geography, a ?geographical imagin ary? is typically treated as a more or less un conscious and unreflective construction, but it is rarely given any formal theoretical inflec tion. It usually refers to a spatial ordering that is tied either to the collective object of a series of imaginative geographies (e.g. ?the geographical imaginary of the Tropics?: see tropicaLity) or to their collective subject (e.g. ?the imperial geographical imaginary?). Watts (1999) brilliantly combines the two in an ex ceptionally careful reconstruction of the ways in which the Ogoni people of the Niger delta fashioned a precarious sense of collective iden tity tied to space, territory and land. Like Watts, most studies recognize the crucial im portance of language, especially metaphor, and of visuaLity in producing these orderings. (NEW PARAGRAPH) Geographical imaginaries involve bordering as well as ordering: the hierarchical division of the globe into continents, states and other sub categories (see scaLe), for example, and the oppositions between global north/south, urban/rural, inside/outside and cuLture/na ture. These divisions also often act as tacit valorizations (?civilized?/?savage?, for example, or ?wild?/?safe?) that derive not only from the cognitive operations of reason but also from structures of feeling and the operation of affect. As such, geographical imaginaries are (NEW PARAGRAPH) more than representations or constructions of the world: they are vitally implicated in a material, sensuous process of ?worlding?. Thus, for example, Howitt (2001a, pp. 236 7) identified a geographical imaginary that was intimately involved in the European construc tion of a ?bounded self? and which, in the colo nial past of austraLia and on into its present, worked to construct equally bounded spaces ?that provided certainty, identity and security? from which indigenous peoples were exclu ded. More generally, but closely connected, Massey (2004, pp. 9 10) attributed a pervasive ?Russian doll geography of care and responsi bility? to ?the persistence of a geographical im aginary which is essentially territorial and which focuses on the near rather than the far?. It follows that a vital critical task for human geography is the disclosure of these taken for granted geographical imaginaries and an examination of their (often unacknowledged) effects. dg (NEW PARAGRAPH) Suggested reading (NEW PARAGRAPH) Watts (1999). (NEW PARAGRAPH)

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