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Basic Geography Geography means writing about the earth. The term was coined by Eratosthenes (276-194 BCE). Geography is the spatial science. It is related to Astronomy, Geology, Demographics, Anthropology, Economics, and other social sciences. The Greeks and Romans believed that the earth was a sphere, but thought that it was at the center of the cosmos. The sun, moon, and planets all rotated around the earth. This is the geocentric theory of the cosmos. Not until the sixteenth and seventeenth centuries, did the heliocentric theory come to prevail. Copernicus, Brahe, Kepler, Galileo, and Newton created the modern, scientific view of the universe. The Greeks and Romans did, however, develop a grid system for mapping locations. During the Middle Ages, scientific knowledge and geography were in decline. With the Voyages of Discovery, Europeans began to gain new knowledge of and to map the entire planet. Tremendous progress has been made since then. Geography begins with mapping the physical and cultural landscape. It links physical and cultural geography. It can also focus on regional (area) and locational studies. The key concepts of geography as a spatial science are location, distance and direction. Each of these terms may be absolute or relative. Other concepts include scale, size, place. Spatial attributes may be physical and cultural. Places and sites have spatial interactions with each
other. Interactions depend on accessibility Regions may be formal or functional. Mapping the Earth The earth is a sphere. In order to map it, it is divided into parallel lines of latitude. These lines go east and west. Starting at the equator, which is located at 0 degrees latitude, we move north and south 90 degrees from the equator.. The North Pole is at 90 degrees North and the South Pole is at 90 degrees South. All degrees of latitude are parallel to each other.
Lines of Longitude or meridians run north and south from the North Pole through the center of the earth to the South Pole. They are each true circles. The Prime Meridian is arbitrarily placed at Greenwich Observatory in England. International agreements have designated it as the base line for measuring east and west 180 degrees. The International Date Line is at 180 degrees East or West of Greenwich or 0 degrees Longitude. Longitude lines are widest at the equator and converge at the poles. Every 15 degrees East Longitude adds an hour to Greenwich Mean Time. Every 15 degrees West subtracts an hour from Greenwich Mean time. When it is 7 a.m. Eastern Standard Time in New York City, it is noon at Greenwich Mean Time in London. There is a five hours difference.
Mapping a sphere onto a two dimensional flat surface always creates some distortions. Nonetheless placing lines of latitude and longitude together on a map creates a grid system. All places on earth (or on a map) can be accurately located by giving measurements in terms of latitude and longitude. Degrees can be further subdivided into minutes and seconds. 1 degree = 60 minutes This coordinate systems provides for the absolute location of any place on earth. Climate Regions Daily weather patterns measured over years provides the basis for generalizing about climate. Daily weather is measured in terms of temperature, wind speeds, and precipitation. Climates describe typical weather patterns on a yearly cycle. Weather and therefore climate depend largely on where on earth a place is located. Places closer to the Equator receive more insolation than does the North or South Pole. The Koeppen system classifies weather into six broad climate regions labelled A, B, C, D, E, and H. Temperatures and level of precipitation are used as the the two primary variables to create this system. Starting at the equator, we get the following classification system: A. Tropical Climates B. Dryland Climates C and D. Humid Midaltitude E. Arctic and Subarctic H. Highland |
![[IMAGE: Lines of latitude]](maps.h5.gif)
![[IMAGE: lines of longitude]](maps.h6.gif)