2. An organized collection of computer hardware, software, geographic data, and personnel designed to efficiently capture, store, update, manipulate, analyze, and display all forms of geographically referenced information which can be drawn from different sources, both statistical and mapped.
3. Computer programs linking features commonly seen on maps; such as, roads, town boundaries, and water bodies, with related information not usually presented on maps; for examlple, type of road surface, population, type of agriculture, type of vegetation, or water quality information.
GIS is a unique information system in which individual observations can be spatially referenced to each other.4. A technology that is used to view and analyze data from a geographic perspective. The technology is a piece of an organization's overall information system framework.
GIS links locations to information; such as, people to addresses, buildings to parcels of land, or streets within a network, and layers that information to give a better understanding of how it all interrelates. The user can than choose which layers to combine based on his/her purpose.
There's more information at the Geographic Information System (GIS): Index
"Differentiation of populations of biological groups in various geographical isolations to the point where they are recognized as separate species."
2. The quantities of latitude and longitude which define the position of a point on the surface of the earth with respect to the reference spheroid.
This theory suggests that landscapes go through three stages of development (youth, maturity, and old age) and indicates that the rejuvenation of landscapes arises from tectonic uplift of the land.
In the "youthful stage", under the influence of tectonic uplifts, there appears a mountain relief, which is dissected through erosion (the washing out of rocks by rivers) into deep, narrow valleys and sharp-peaked ridges.
With the dissection by streams, the area would reach maturity and, ultimately, would be reduced to an old-age surface called a peneplain (gently undulating, almost featureless plain), with an elevation near sea level.
The model developed by Davis, though important in historical context, is currently considered only a first approximation.
Developments in the sciences of geology and geomorphology, especially the plate tectonics revolution of the 1960's and 1970's, have confirmed the preliminary nature of the model.
The fundamental differences between land and ocean, latitudinal differences in insulation, spatial variations in receipts of precipitation, and patterns of geological composition, and deformation of the earth's crust together provide the basis for distinguishing definite geographical patterns of resource availability through out the world.
2. A computerized system which relates and displays data collected from a geographic entity in the form of a map.
The ability of a geographical information system to overlay existing data with new information and display it in color on a computer screen and is used primarily to conduct analyses and make decisions related to geology, ecology, land use, demographics, transportation, and other domains, most of which relate to the human use of the physical environment.
Through this process of geocoding, the geographic data from a database is converted into images in the form of maps.
2. The total area occupied by a population.
3. The extreme distance at which an object or light can be seen when limited only by the curvature of the earth and the heights of the object and the observer.
2. An orderly arrangement of lines in which an area is defined in relation to one or more geographical points on the earth.
A geographic unit can vary in scale depending on the criteria used, the level of inventory and analysis needed, and the problems perceived. In all cases, geographic units incorporate both groundwater and surface water.