GIS Mapping


A geographic information system (GIS) allows us to view, understand, question, interpret, and visualize data in many ways that reveal relationships, patterns, and trends in the form of maps, globes, reports, and charts. Geographic information system (GIS) technology can be used for scientific investigations, resource management, and development planning. For example, a GIS might allow emergency planners to easily calculate emergency response times in the event of a natural disaster, or a GIS might be used to find wetlands that need protection from pollution.

What is a GIS?

A GIS is a computer system capable of capturing, storing, analyzing, and displaying geographically referenced information; that is, data identified according to location. Practitioners also define a GIS as including the procedures, operating personnel, and spatial data that go into the system.

How does a GIS work?

Relating information from different sources

The power of a GIS comes from the ability to relate different information in a spatial context and to reach a conclusion about this relationship. Most of the information we have about our world contains a location reference, placing that information at some point on the globe. When rainfall information is collected, it is important to know where the rainfall is located. This is done by using a location reference system, such as longitude and latitude, and perhaps elevation. Comparing the rainfall information with other information, such as the location of marshes across the landscape, may show that certain marshes receive little rainfall. This fact may indicate that these marshes are likely to dry up, and this inference can help us make the most appropriate decisions about how humans should interact with the marsh. A GIS, therefore, can reveal important new information that leads to better decisionmaking.



Nationwide GIS Mapping




GIS Mapping by State

  • Alabama
  • Alabama Metadata Portal
  • Alabama Water Quality Information System
  • Alaska
  • Alaska Geospatial Data Clearinghouse
  • Arizona
  • Arizona Electronic Atlas
  • Arkansas
  • Arkansas GIS Gateway
  • Arkansas AR-GAP
  • California
  • California Spatial Information Library (CaCIL)
  • California Land Use Planning Information Network (LUPIN)
  • Northern Sierra Nevada GIS
  • Colorado
  • Southwestern Colorado Data Center
  • Conneticut
  • Map and Geographic Information Center (MAGIC)
  • Connecticut Department of Environmental Protection
  • Delaware
  • Delaware Spatial Data Clearinghouse
  • Florida
  • Florida Geographic Data Library
  • Georgia
  • Georgia Spatial Data Infrastructure
  • Hawaii
  • City & County of Honolulu Dept. of Planning and Permitting
  • State of Hawaii Office of Planning GIS
  • Idaho
  • Inside Idaho
  • Idaho Department of Water Resources
  • Illinois
  • Illinois Natural Resources Geospatial Data Clearinghouse
  • Indiana
  • Indiana GIS Initiative
  • Iowa
  • Iowa Geographic Information Council (IGIC)
  • Kansas
  • Kansas Geospatial Community Commons
  • Kentucky
  • Kentucky Geological Survey
  • Kentucky Office of Geographic Information (KYGI)
  • Louisiana
  • Atlas: The Louisiana Statewide GIS
  • Louisiana Geographic Information Center (LAGIC)


  • Maine
  • Maine Office of GIS
  • Maryland
  • Maryland Historical Trust
  • Massachusetts
  • Massachusetts GIS
  • Michigan
  • Michigan Center for Geographic Information
  • Minnesota
  • Minnesota Geographic Data Clearinghouse
  • Minnesota Legislative Geographic Information Services
  • Mississippi
  • Mississippi Automated Resource Information System (MARIS)
  • Missouri
  • Missouri Spatial Data Information Service (MSDIS)
  • Montana
  • Natural Resource Information System (NRIS)
  • Nebraska
  • Nebraska Geospatial Data Bank
  • Nevada
  • Nevada Bureau of Mines & Geology
  • New Hampshire
  • New Hampshire GRANIT
  • New Jersey
  • New Jersey Geographic Information Network (NJIN)
  • New Jersey Dept. of Environmental Protection, GIS
  • New Mexico
  • New Mexico Resource Geographic Information System (RGIS)
  • New York
  • NYC OASIS
  • BYTES of the BIG APPLE
  • Cornell University Geospatial Information Repository (CUGIR)
  • NY State GIS Clearinghouse -
  • NYS Office of Cyber Security & Critical Infrastructure Coordination Orthoimagery Interactive Mapping Gateway
  • North Carolina
  • North Carolina Geographic Data Clearinghouse
  • NCSU Libraries County GIS Data
  • North Dakota
  • North Dakota Geographic Information Systems (NDGIS)
  • Ohio
  • Ohio Geographically Referenced Information Program (OGRIP)
  • Oklahoma
  • Oklahoma Center for Geospatial Information
  • Oklahoma State GIS Council
  • Oregon
  • Oregon Geographic Data Clearinghouse (OGDC)
  • Pennsylvania
  • Pennsylvania Spatial Data Access (PASDA)
  • Penn State University Libraries Maps & Data: Interactive Data Sources
  • Rhode Island
  • University of Rhode Island Natural Resource and Environmental Management
  • South Carolina
  • South Carolina Dept. of Natural Resources GIS Data Clearinghouse
  • South Dakota
  • South Dakota Geological Survey Program
  • Tennessee
  • Tennessee Spatial Data Server
  • TNMap
  • Texas
  • Texas Natural Resources Information System (TNRIS)
  • Texas Water Development Board
  • Utah
  • Utah GIS Portal
  • Vermont
  • Vermont Center for GIS (VGIC)
  • Virginia
  • Virginia Geographic Information Network
  • Washington
  • Washington State Geographic Information Council (WSGIC)
  • Washington State Dept. of Natural Resources GIS
  • West Virginia
  • West Virginia State GIS Technical Center
  • Wisconsin
  • Wisconsin Land INformation Clearinghouse (WISCLINC)
  • Wyoming
  • Wyoming Geographic Information Science Center









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