Homepage | Publications |  Software |  Indicators |  Animation |  Geo |  blog |  Search website (Google)


Portfolio analysis in terms of maps


The routines provided on this page (below) follow up on the overlaytoolkit which Ismael Rafols and I created in 2007 as an appendix to Leydesdorff et al. (2009; Leydesdorff et al. 2013; Carley et al., 2017l; Riopelle et al., 2014).


This instrument was updated in 2008, 2009, 2010, and 2015. This new update is based on 2019 data. The new paper is:

Leydesdorff , L. (2021). Automation of the Overlaying in the case of Journal Maps. under submission.


Introduction and instruction 

Overlay maps are overlays on the basis of a global map of science. The steps described below rely on access to the Web of Science and the files available in our mapping kit. The objective is to obtain the set of Web-of-Science Categories (WCs) for a given set of articles; provide this to network software; and output overlay information to add to a suitable basemap. We describe here below the procedures for using VOSviewer. The interface with Pajek is not elaborated here, but can be constructed by the user using the output files and the cosine matrix.  


Additionally, a variant of wc19.exe reads a file (re)named "data.txt" in the same  folder. "Data.txt" contains records downloaded from WoS in the "plain text" format.  There is no limitation on the  number of records. This variant is called  wc19docs.exe. Thus, the user has two options. The results are identical.


In addition to the data and the respective routine, one needs to download in the same folder; cosine.dbf, cosmap.dbf , and cos19net.txt .


The program generates a number of outputs:


 1. input files for VOSviewer. If VOSviewer.exe is available at  C:\vowviewer\vosviewer.exe a portfolio map will be automatically gnerated. WCs used  in the set will be foregrounded.


2. the file sc.dbf contains the portfolio data.  


3. the file div_wc19.dbf contains the interdisciplinarity and diversity  indicators for this sample in the bottom line. If the file  div_wc19 does not yet exist, it will be generated. If it already exists, a record is added at the bottom with the  various values. (This same file is similarly used at the  journal level.) Div_wc19.dbf contains interdisciplinarity  indicator-values such as Roa-Stirling, DIV*, Gini,  variety, disprity, etc. Disparity is based on (1 - cos)  for the distance within the compoed indictorsa. One is prompted for the name of the run.



@ Loet Leydesdorff, 2009, 2010, 2012, 2016, 2019, 2021.

Amsterdam, 23 January 2021



Leydesdorff, L., & Rafols, I. (2009). A Global Map of Science Based on the ISI Subject Categories. Journal of the American Society for Information Science and Technology, 60(2), 348-362. doi: 10.1002/asi.20967

Leydesdorff, L., Carley, S., & Rafols, I. (2013). Global Maps of Science based on the new Web-of-Science Categories Scientometrics, 94(2), 589-593; available at doi: 510.1007/s11192-11012-10783-11198 

Carley, S., Porter, A. L., Rafols, I., & Leydesdorff, L. (2017). Visualization of Disciplinary Profiles: Enhanced Science Overlay Maps. Journal of Data and Information Science (JDIS), 2(3), 68-111. doi: 10.1515/jdis-2017-0015

Riopelle, K., Leydesdorff, L., & Jie, L. (2014). How to Create an Overlay Map of Science Using the Web of Science http://www.leydesdorff.net/overlaytoolkit/manual.riopelle.pdf.