Free or Inexpensive GIS Resources Available on the Web

by



Mark Francek, Central Michigan University (Mark Francek@cmich.edu)

Tammie Grant, Salish Kootenai College (tamgrant@comcast.net)

Cindy Schmidt, NASA Ames Research Center (cschmidt@mail.arc.nasa.gov)

David Tewksbury, Hamilton College (dtewksbu@hamilton.edu)

Wei Tu, Georgia Southern University (wtu@georgiasouthern.edu)

Xingyou Zhang, Georgia Southern University (xyzhang@georgiasouthern.edu)






A Geographic Information System (GIS) is a hardware/software system allowing users to assemble, integrate, query, and map spatially referenced information. Prior to the advent of GIS, which began to be widely adapted for teaching and research in the late 1980’s, population patterns, soils, landuse, transportation, topographic, and hydrologic data were often mapped separately and then combined through the use of map overlays. Combining so many layers was often cumbersome and difficult to interpret. Now, with the advent of GIS, users can quickly combine map layers to create new mapping perspectives, query attributes, calculate distances, and create buffers.

The ability of GIS to integrate map features, demonstrate patterns, and create models has been recognized by the public and private sectors, spurring the growth of GIS course offerings in geography and geoscience departments as well as many other disciplines such as urban planning and natural resource management. With an increased emphasis of GIS in the curriculum has come the need to discover sources of reliable free or inexpensive datasets for student projects and exercises.

This web review focuses on free or inexpensive GIS data available on the web. Most datasets are in a compressed format and will need to be unzipped with a file decompression program. These files, which include shapefiles, digital ortho imagery, and digital elevation models can then be viewed and manipulated with commercially available GIS software. Note that some of the sites will require that pop up and cookie blockers be temporarily turned off for the download process. In addition, most sites require Java-enabled, recent versions of popular web browsers such as Internet Explorer, Netscape, and Firefox.

The sites suggested are a product of discussions associated with the “Course Design” workshop offered as part of the NSF supported “On the Cutting Edge” professional development series for geoscience faculty. The suggested sites are not the only sources of information but do represent some of the better sites for obtaining GIS data for student research projects and exercises. To share a particularly relevant GIS resource for dissemination to the earth science community through the “Earth Science Site of the Week” listserv, please contact Mark Francek (Mark.Francek@cmich.edu).