Changes in what a discipline studies are closely interwoven with changes in how its research is undertaken. Some substantive changes have been technologically driven: without new facilities, advances would not have been possible, perhaps not conceivable. In others, technical developments were responses to the research questions.

Physical geography has experienced two parallel sets of methodological changes since 1970. The first involved closer alliances with other scientific disciplines, engaging with the physical, chemical, and biological bases for understanding physical matter and processes together with the mathematical methods necessary for their analysis. The second involved technical developments in field and laboratory measurement and data analysis. These two have come to pervade all work in physical geography, which has become technically sophisticated and whose progress has depended almost entirely on such skills.

Virtually all work in physical geography shares a belief in what is known as the “real” world—that which can be observed, measured, and generalized upon, even if the appreciation of particular events and landforms requires setting general principles within particular contexts. The laws of physics can be used to generalize about atmospheric processes, for example, but only an appreciation of how they interact in specific, local circumstances can account for the weather at a place on a given day. Immanent laws operate in local, contingent circumstances, involving highly complex interactions whose analysis requires sophisticated mathematical skills in analyzing nonlinear, often chaotic, relationships.

A much wider range of approaches is deployed within human geography; different theories of knowledge and reality inspire different types of work. The tenets of positivism still underpin some work in many areas: there is order in the world that can be observed, measured, analyzed, and generalized, even if there are no general laws of human behaviour awaiting discovery. Other work is based on theories of knowledge that claim an inseparability of observer and observed (or subject and object) and dispute the existence of real worlds independent of their inhabitants’ imagined worlds. We cannot apprehend an external world but only perceived worlds. Geographical research based on these premises deploys means of identifying those worlds, the processes involved in their creation, and the behaviour within them. It then has to transmit that derived understanding to others—what is sometimes termed a “double hermeneutic.”

These various approaches pervade most of contemporary human geography. With the exception of cultural geography, quantitative methods are used to analyze and identify regularities in data sets large and small, taking advantage of technical advances, such as with methods of artificial intelligence for classifying individuals and areas.

Nonquantitative approaches can be found throughout the various subdisciplines. These involve obtaining information in rigorous ways from individuals regarding their mental maps of the world and how these underpin behaviour. Means of interviewing individuals and groups to elicit information dominate the qualitative procedures that involve interpersonal interaction. Research material is also sought in a variety of other ways, through, for example, participant observation in case studies of communities and events. But information gathering extends well beyond interacting, directly or indirectly, with living people. Learning about the roles of places, spaces, and environments in the lives of individuals, groups, communities, and even entire societies near as well as far and past as well as present involves interrogating many information sources. Most common are written texts, analyzed for the meanings they can reveal. Other documents, such as maps, also reveal much, as do works of art. Ways of deconstructing meanings are commonly used in cultural and historical geography and in other subdisciplines too, as with the meanings attached to exotic foods in economic geography.

Research involves not only observing, recording, and analyzing the world but also transmitting acquired understandings and explanations to others. In quantitative analyses, this involves using mathematical notation and procedures—a language that many claim is unambiguous but whose use nearly always involves interpretation in vernacular languages, with meanings often contested. In qualitative work, nearly all of the reporting is done through the medium of written language. Having studied texts to reach understandings, researchers then deploy the same media to present them to others and thereby place their readers in the same situation of having to derive meanings from the textual material. The research process thus involves continued interpretation and reinterpretation of textual and other materials, including research reports. Unlike the apparently incontestable clear statements of quantitatively expressed research findings, research in much contemporary human geography involves continued debate over meanings and interpretations.

One tool long considered central to geographical work is the map. Automation of map production has been accompanied by a decline of research in this area; one of the few continuing fields concerns map legibility—the degree to which different symbols and shading succeed in transmitting messages. Its replacement as a central tool is GIS, a visualization medium with massive capacity for facilitating a wide range of research investigations. It offers not only sophisticated procedures for manipulating spatial data but also new ways of presenting visual data, including three-dimensional images of the world, at all scales. Geographic information science incorporates the traditional disciplines of cartography, geodesy, and photogrammetry with modern developments in remote sensing, the Global Positioning System (GPS), geostatistics, and geocomputation in activities that bring forward geographers’ eternal interest in maps as sophisticated means of representing, analyzing, and viewing the Earth’s great diversity.

Applied geography

One area that some have set apart from the various subdisciplinary divisions concerns the application of geographical scholarship. Geography was always applied, long before it became an identified academic discipline; much geographical knowledge was created for specific purposes. Since the discipline was established, individuals have used their knowledge in a wide range of contexts and for various types of clients. Outside of universities, some of those trained as geographers have applied their skills in a range of sectors; the U.S. State Department had an Office of the Geographer for much of the 20th century, for example, providing the president with daily briefings.

For the first half of the 20th century, the development of geography as an academic discipline was closely associated with its educational role, especially in the preparation of teachers and of teaching materials. Increasingly, however, geographers responded to societal changes—especially the extending role of the state—by promoting their discipline as a potential contributor in a range of activities. Some, like L. Dudley Stamp, argued that geographers’ factual knowledge regarding environments and places plus their understanding of spatial organization principles should be applied in town, city, country, and regional planning. This could just involve information provision, but increasingly it was argued that geographical analyses could inform the understanding of current patterns and trends and the preparation of plans for the future.

Such geographical involvement expanded in the late 20th century as pressures grew on universities to orient their work more to societal needs and to undertake applied research for public- and private-sector sponsors. Within human geography, for example, the locational analysis paradigm was adapted to commercial applications. Models of least-cost (and hence economically most efficient) location were used to predict the best sites for facilities, such as supermarkets and hospitals. Classifications of residential areas within cities were adapted to identify districts dominated by people with particular lifestyles toward which niche-market advertising could be directed; this substantial activity is widely termed geodemographics. Qualitative research findings and methods have been deployed in resolving conflicts over proposed land uses at particular sites.

Physical geographers’ understanding of environmental processes has been directed to applied ends to meet concerns over environmental issues; much public policy takes these issues into account when pursuing goals such as sustainable development. Four types of applied work have been identified: description and auditing of contemporary environmental conditions; identification and analysis of environmental impacts, mainly of human action, actual and proposed; evaluation of the value of particular environments for specified future uses; and prediction and design of environmental works.

Some of these studies are relatively small-scale, such as tracing the diffusion of pollutants through water channels, identifying mineral deposits within local ecosystems, and monitoring local environmental changes and processes. Others involve larger-scale activities, such as models of climate change used to predict future ice-sheet melting, sea levels, and limits of cultivation of various plants. The scientific research may feed wider debates over policy formulation or may incorporate action plans—for conserving specific landscapes (such as wetlands or coasts) or managing a river catchment—as shown through the work of physical geographer William L. Graf, who chaired such interdisciplinary National Research Council studies as Strategies for America’s Watersheds (1999) and Dam Removal: Science and Decision-Making (2002).