*****  To join INSNA, visit  *****

Interactive Overlays: A New Method for Generating Global Journal Maps from
Web-of-Science Data

Loet Leydesdorff & Ismael Rafols

Recent advances in methods and techniques enable us to develop an
interactive overlay to the global map of science based on aggregated
citation relations among the 9,162 journals contained in the Science
Citation Index and Social Science Citation Index 2009 combined. The
resulting mapping is provided by VOSViewer. We first discuss the pros and
cons of the various options: cited versus citing, multidimensional scaling
versus spring-embedded algorithms, VOSViewer versus Gephi, and the various
clustering algorithms and similarity criteria. Our approach focuses on the
positions of journals in the multidimensional space spanned by the
aggregated journal-journal citations. A number of choices can be left to the
user, but we provide default options reflecting our preferences. Some
examples are also provided; for example, the potential of using this
technique to assess the interdisciplinarity of organizations and/or document
pdf-version 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
[log in to unmask] ; 
Visiting Professor, ISTIC, Beijing; Honorary Fellow, SPRU, University of

SOCNET is a service of INSNA, the professional association for social
network researchers ( To unsubscribe, send
an email message to [log in to unmask] containing the line
UNSUBSCRIBE SOCNET in the body of the message.