Urban and transportation geographers study cities and metropolitan areas, while regional geographers study the physical, climatic, economic, political, and cultural characteristics of regions, ranging in size from a congressional district, to a State, country, continent, or the entire world. Medical geographers study health care delivery systems, epidemiology, and the effect of the environment on health. GIS is widely used in weather forecasting, emergency management, resource analysis and management, and other activities. Historians research and analyze the past. They use many sources of information during their research, including government and institutional records, newspapers and other periodicals, photographs, interviews, films, and unpublished manuscripts such as diaries and letters.
Biographers collect detailed information on individuals.
Genealogists trace family histories. Other historians help study and preserve archival materials, artifacts, and historic buildings and sites. Political scientists study the origin, development, and operation of political systems. They conduct research on a wide range of subjects such as relations between the United States and foreign countries, the beliefs and institutions of foreign nations, for example those in Asia and Africa, the politics of small towns or a major metropolis, or the decisions of the U.S. Supreme Court. Studying topics such as public opinion, political decisionmaking, and ideology, they analyze the structure and operation of governments as well as informal political entities.