, Volume 94, Issue 2, pp 589-593

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

Global maps of science based on the new Web-of-Science categories

  • Loet LeydesdorffAffiliated withAmsterdam School of Communication Research (ASCoR), University of Amsterdam Email author 
  • , Stephen CarleyAffiliated withSchool of Public Policy, Georgia Tech
  • , Ismael RafolsAffiliated withSPRU (Science and Technology Policy Research), University of Sussex


In August 2011, Thomson Reuters launched version 5 of the Science and Social Science Citation Index in the Web of Science (WoS). Among other things, the 222 ISI Subject Categories (SCs) for these two databases in version 4 of WoS were renamed and extended to 225 WoS Categories (WCs). A new set of 151 Subject Areas was added, but at a higher level of aggregation. Perhaps confusingly, these Subject Areas are now abbreviated “SC” in the download, whereas “WC” is used for WoS Categories. Since we previously used the ISI SCs as the baseline for a global map in Pajek (Pajek is freely available at http://​vlado.​fmf.​uni-lj.​si/​pub/​networks/​pajek/​) (Rafols et al., Journal of the American Society for Information Science and Technology 61:1871–1887, 2010) and brought this facility online (at http://​www.​leydesdorff.​net/​overlaytoolkit), we recalibrated this map for the new WC categories using the Journal Citation Reports 2010. In the new installation, the base maps can also be made using VOSviewer (VOSviewer is freely available at http://​www.​VOSviewer.​com/​) (Van Eck and Waltman, Scientometrics 84:523–538, 2010).


Map Overlay Web of Science Subject categories Interdisciplinarity