Geography Glossary - G

geographic information system (GIS)

A computerized system for the collection, storage, and retrieval of geographic data

geography

Literally, writing about the earth, Greek. The study of the earth's physical and human features. See "What is Geography?" and "Definitions of Geography" on this site

geologic time

The calendar of the earth's history since its birth 4.6 billion years ago; geologic time is divided into eras, epochs, and periods

geology

Science of the earth's crust, strata, origin of rocks, etc.

geomorphology

The study of the landscapes of the earth and their development

geophagy

Eating dirt or clay

gerrymandering

The process of redistricting voting boundaries to benifit one group over another

glacier

A large mass of ice thad moves over the land, carving and eroding surfaces as it moves

global positioning system (GPS)

A system of satellites and ground units which enable a user to determine their absolute location

global warming

The theory that temperature of the atmosphere an increasing due to the increase in gasses such as carbon dioxide

globe

A spherical model of the earth's surface that includes a map of the earth; also known as a terrestrial globe

great circle

Any hypothetical circle that passes through the center of the earth and divides the planet into two hemispheres. The great circle route, following the arc of a great circle on the earth's surface is the shortest route between any two places on earth. The equator is the only line of latitude that is a great circle.

green revolution

The effort to introduce highly effective crops to the developin world in the 1960s

greenhouse effect

The analogy used to describe the ability of gasses in the atmosphere to absorb heat from the earth's surface

gross national product (GNP)

The value of all goods produced in a given country during a year

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