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Interactive Overlays on the basis of Aggregated Journal-Journal Citations

The overlays can be made on the basis of any download from the (Social)
Science Citation Index at the Web-of-Science in the (so-called) tagged
format. The procedure for generating overlay maps on the basis of journals
is analogous to the one for 2009 data described in: Loet Leydesdorff &
Ismael Rafols, Interactive Overlays: A New Method for Generating Global
Journal Maps from Web-of-Science Data, Journal of Informetrics 6(3) (2012),
318-332. The number of journals included in 2011 is 10,675 (JCR 2011 for the
Science Edition and Social Science Edition combined, v. 1; July 2012).

The single major difference with the previous maps is clustering on the
basis of the decomposition algorithm of Blondel et al. (2008) as default.
Previously, we used clustering as provided by VOSViewer (Waltman et al.,
2010). However, the two clustering results are both available, and the user
can change this option. Examples and instruction are provided at .

** apologies for cross-postings
Loet Leydesdorff 
Professor, University of Amsterdam
Amsterdam School of Communications Research (ASCoR)
Kloveniersburgwal 48, 1012 CX Amsterdam.
Tel. +31-20-525 6598; fax: +31-842239111
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