Geographic data is increasingly available over the internet at publicly-accessible clearinghouses. These websites typically list data elements, metadata (or other kinds of "data about the data" that describe source, date, projection, and limitations) and instructions on how to access specific files. Some websites are limited to public data; others also include private data that is available for purchase. We expect the role of internet-based clearinghouses as a data distribution mechanism will continue to grow over time. For more information and links to clearinghouses, see the "Data Resources" on our website: http://cml.upenn.edu. (top)
2000 Census data
Data from the 2000 Census is being released in phases, starting with the general population counts required for legislative redistricting in 2001. Other summary files with more detailed demographic and geographic breakdowns will follow over the next two years. Data from the 2000 Census will be widely available in electronic formats over the internet. Frequently requested 2000 Census data elements will be available over the web through
the American Fact Finder website.
This menu-driven site is designed to make it easy for the public to customize requests and download data. In addition to tabular data, American Fact Finder includes an internet map server application that allows users to generate maps over the web. This tool will allow users to visualize spatial relationships in the data without requiring any formal GIS training or specialized GIS software.
The Penn Library
also maintains a website with information about the
2000 Census. This
page provides quick links to Census 2000 resources developed by the Penn Library
or provided through other web publishers, including the U.S. Bureau of the
. 1990 Census data
Wessex data (for 1990 Census shapefiles)
Philadelphia shapefiles (this site, "GIS Data Resources")
Geographic data from CML research projects
With the exception of publicly accessible (unrestricted) data, any dataset and/or shapefile developed through a CML research project belongs to the project's Principal Investigator (PI).
The CML will defer to the PI regarding who may access the data.
Requests to access data by persons not directly involved with the project must be made in writing to the Principal Investigator (PI). The PI must authorize access to specific project databases, shapefiles or data elements in writing to the Managing Director of the CML. The CML will copy and distribute the data according to the written instructions from the PI.
Data obtained from Third Parties
The CML may obtain data from third parties such as city agencies or private vendors. In some cases, the original owners of the data may put restrictions on its use or distribution (e.g., grant permission to use a shapefile for a specific project only.) The CML respects the rights of its data providing partners to control use and distribution of their data and will honor all agreements regarding data use and access.
The CML will uphold all commitments it makes with third parties concerning restrictions on the use and reuse of data. Persons requesting access to restricted files must obtain written permission from the original owner of the data expressly authorizing the CML to release it to specifically named individuals. The authorization should include: the of the person who is granting the CML permission to share data, a description of the specific data to be shared and the name of the person who is to be on the receiving end of the data.
Comments or questions
about this policy should be directed to:
Cartographic Modeling Lab
University of Pennsylvania