Scalable Vector Graphics (SVG)
In early September 2001, the World Wide Web Consortium approved Scalable Vector Graphics
(SVG) as a recommended new standard for the two-dimensional display of graphics, text
and animation. CCI believes that SVG offers great promise for dyanmic data
visualization or on-the-fly graphics cum text generated from a database. Pending
adoption of SVG by the major browser manufacturers, it is necessary to add a
plug-in to your browser in order to view SVG graphics. You can
download a plug-in from Adobe that will work for Microsoft Internet Explorer or Netscape Navigator at
http://www.adobe.com/svg/viewer/install/).
Technical notes and source code:
The 1789-1998 maps are
dynamically generated from a database file. If your computer and
Internet connection are slow, please be patient. Click here for the source code.
Static files produce the SVG images for the 106th Congress.
They are based on Poole and Rosenthal data imported into FoxPro tables
and generated by a FoxPro program. Click here for the source code.
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Ideological Maps of the U.S. Congress
Ideological Maps of U.S. Senates (1789-1998)
Ideological Maps of the 106th U.S. House and Senate (1999-2000)
These ideological maps are based on scores developed by political scientists
Keith Poole and Howard Rosenthal.
The interpretation of the ideological significance
of the Senate maps ranging from 1789 through 1998
varies from one period to another. The left-right dimension generally
corresponds to a liberal-conservative split over the economic role of the federal government.
The vertical dimension often captures differences within political parties over issues like
slavery and racial politics. Color-coded legends identify Senators' political parties. (For a veritable rainbow of parties,
check out Congresses like the 18th or the 56th).
In the most recent Congresses including the 106th depicted here,
social conservatives (on issues like abortion or school prayer) gravitate to the top and social liberals to the bottom.
In response to a question from CCI,
Dr. Poole confirmed that, for the 106th Congress, it is OK to depict
liberals and conservatives along social and economic lines with
the legends below. The left-right dimension corresponds to
a liberal-conservative split over the economic role of the federal government.
On the vertical dimension issues like abortion or school prayer pull
social conservatives toward the top and social liberals toward the bottom.
Dr. Poole made the following qualification: "Technically, the 2nd
dimension is *very* weak -- the 106th Congress is essentially one
dimensional. The 2nd dimension picks up a lingering North-South
divide (South near the top of the dimension, North near the bottom).
This essentially is picking up what few moderate-conservative
Southern Democrats there are left in Congress. The 2nd dimension
also helps to account for abortion voting."
For a discussion of Poole and Rosenthal's methodology see Congress: A Political-Economic History of Roll Call Voting (Oxford University Press, 1997).
The data are available at Keith Poole's site
http://voteview.uh.edu/.
Ideological Maps of U.S. Senates (1789-1998)
Ideological Maps of the 106th U.S. House and Senate (1999-2000)
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