***** To join INSNA, visit http://www.insna.org ***** 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 sets. http://arxiv.org/abs/1105.2925 pdf-version at http://arxiv.org/ftp/arxiv/papers/1105/1105.2925.pdf ** 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] ; http://www.leydesdorff.net/ Visiting Professor, ISTIC, Beijing; Honorary Fellow, SPRU, University of Sussex _____________________________________________________________________ SOCNET is a service of INSNA, the professional association for social network researchers (http://www.insna.org). To unsubscribe, send an email message to [log in to unmask] containing the line UNSUBSCRIBE SOCNET in the body of the message.