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GIS (Geographic Information Systems): Data

Free GIS Data & Imagery GeoBlog

Public domain GIS data and Free GIS data repositories and clearinghouses
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Recommended Data Sources

UNdata: "largest and most authoritative compilation of United Nations and agency statistics ever compiled, covering economic, social, financial and development topics containing more than 350 series"

Conservation Geoportal "lets users quickly find and evaluate data and maps for any consevation topic or geography and provides a convenient place for anyone to publish maps and data."

Some Questions to Consider

For most GIS projects, data collection constitutes the largest portion of time and effort put into the project. Locating data for a GIS project is the same as locating data needed to conduct any research project. It should not be assumed that the data needed for a project is readily available.

"When considering data from any existing source, you must answer five key questions:"

1. Do the data contain the information I need for my study?

2. Is the data appropriately documented (metadata) so that I understand how and why it was collected and coded in the way provided?

3. Is the format of the data appropriate for my study, and, if not, will I be able to convert it?

4. Do the data contain a geographic element to link it to the GIS, or, if not, could one be added easily?

5. If there are multiple versions, is this the best one for my purpose?

From Geographic information systems for the social sciences : investigating space and place / Steven J. Steinberg and Sheila L. Steinberg. Thousand Oaks : SAGE Publications, c2006, p. 100.

Locating Data

Many data sets are readily available on the Internet, primarily from four types of providers: government agencies, universities and research organizations, nonprofit organizations, and private firms. Government agencies in the United States and elsewhere have done especially well in making data available online.To locate GIS data on the Internet, begin by reviewing the following list of links: although not intended to be comprehensive, it provides links to many datasets grouped by location, both national and international: GIS data on the Internet.

If you would like to search for data on the Internet, use a search engine such as Google and the phrase GIS Dataset along with keywords specifying location and topic, according to what you are looking for: for example, to find environmental data for the state of Montana, you might use as your search terms GIS Dataset environmental Montana. This will retreive about 650,000 websites, the first of which will be a GIS Data List from a Montana state government website, and the 2nd, the National Resources Information System webpage from the Montana State Government, and so on. As stated above, the data you need may not be readily available. Data from local organizations and agencies may be especially difficult to locate because they may not have the resources to make data available online.

US Census GIS Files, Pennsylvania Spacial Data Access (PASDA), and City of Philadelphia Shape files from PASDA. I

Refer also to the PORTALS TO GIS RESOURCES column on the left side of the OTHER RESOURCES tab in this guide.

GIS Databases

Some databases containing data useful for GIS - more data can be found on this page



OpenDataPhilly includes both municipal and non-municipal data and enables users to search for and locate data sets based on keyword and category searches. Each data set, application, or API includes accompanying information about the origins, update frequency, and other specifics of the data. The record for each data source also includes links for downloading the data or accessing the application or API.

Built by Azavea, a Philadelphia-based Geographic Information Systems (GIS) software firm, it is now operated by the Philadelphia Public Interest Information Network, a Philadelphia-based non-profit organization.

Pennsylvania Spatial Data Access (PASDA)
The official public access geospatial information clearinghouse for the Commonwealth of Pennsylvania and has served for fifteen years as Pennsylvania's node on the National Spatial Data Infrastructure, Geospatial One-Stop, and the National Biological Information Infrastructure
Includes:City of Philadelphia Shape files from PASD

U.S. Census Maps & Data
Find geographic data and products such as the TIGER/Line Shapefiles, KMLs, TIGERweb, cartographic boundary files, geographic relationship files, and reference and thematic maps.

 Atlas of Historical County Boundaries: from the Newberry Library, a dataset that covers every day-to-day change in the size, shape, location, name, organization, and attachment of each U.S. county and state from the creation of the first county in 1634 through 2000. The data are organized by state and are available online in four versions: 1) Viewable, interactive maps; 2)  Downloadable shapefiles; 3) Downloadable KMZ files; and 4) Downloadable and printable PDF files.