GIS stands for
Geographic Information Systems, often defined as a computerized database management
system for capture, storage, retrieval, analysis, and display of spatial data.
Any data that includes information about location—be it a street address,
zip code, census tract, or longitude and latitude coordinates—can be
considered spatial. Many different types of data can be integrated into GIS
and represented as a map layer. When these layers are drawn on top of each
other, spatial patterns and relationships often emerge. The most common GIS
product is a map, but GIS can be used to generate answers to queries or as
part of spatial statistical analysis.
GIS also stands for Geographic Information Science, an emerging interdisciplinary
field that combines elements of geography, cartography, and computer science.
Thought of in this way, GIS is a way of thinking about the world that puts
spatial relationships at the center. GIS technology was originally developed
to model the natural world—landmasses and bodies of water, elevation,
temperature, soil composition, and suitable habitats for animals. More recently,
social scientists have begun applying these tools—and this way of thinking—to
understanding the social and built environment.
Overview of
different formats of spatial data:
Raster and Vector
GIS stores and supports two major categories of data formatting: Raster and
Vector. Vector data represents objects based on distinct points, line or areas
described by their x and y coordinates and their topological relations to
each other. On the other hand continuous surfaces can be better represented
using raster data which are a combination of cells which have values representing
the landscape.
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GIS Resources on the Web
Data Sources:
Dictionary of GIS Terms
National Spatial Data Clearinghouse
Geography
Network
GIS Data
Depot
PASDA
Organizations:
Open GIS Consortium
American
Congress on Surveying and Mapping
National States Geographic
Information Council
University Consortium for
Geographic Information Science California
Geographic Information Association
URISA
Other Online GIS Applications:
Neighborhood Knowledge
Los Angeles
Baltimore Neighborhood Indicators Alliance
Vallejo Economic Development
Information System
Nashville Metropolitan
Planning Department
Map Milwaukee
© 2004 Cartographic Modeling Laboratory
