Loet Leydesdorff, Lutz Bornmann, and Caroline S. Wagner,
Generating Clustered Journal Maps: An Automated System for Hierarchical Classification
The routine (called “decomp.exe”) presumes an input file named “level0.net” containing the 1-mode network file saved in the .net format of Pajek. Decomp.exe begins with running the following statement from the command line:
“C:\vosviewer\vosviewer -pajek_network C:\temp\level0.net -save_map C:\temp\m0.txt -save_network C:\temp\n0.txt -run_layout -run_clustering -repulsion 0 -min_cluster_size 2 -merge_small_clusters true”
VOSviewer is to be installed in the folder C:\vosviewer and one operates in the folder C:\temp . The “minimum cluster size” is set to “two” in order to suppress isolates; repulsion is set to “zero” to optimize the visualizations.
The initial output is written to the files m0.txt for the map and n0.txt for the network (at level 1), respectively. The file m0.txt contains the clustering that is used by the routine for generating an input file for each of the clusters. This next round generates output files m1.txt, m2.txt, etc., as map files of VOSviewer which contain the information for drawing maps at the next-lower level (level 2). In a next round, each of these files is further decomposed into m1_1.txt, m1_2.txt, etc. (level 3). The tree can be found at http://www.leydesdorff.net/jcr15/tree.htm. The two levels are attributed to individual journals at http://www.leydesdorff.net/jcr15/index.htm. Finally, all level-3 files are run in VOSviewer in order to generate the classification at level 4. This classification is attributed to each journal as a hyperlink at http://www.leydesdorff.net/jcr15: by clicking on a journal name, one webstarts VOSviewer to generate a map of the citation environment of this journal at level 4. The user can save this map for further decomposition (at level 5; see below).
See for further instruction and explanation: Loet Leydesdorff, Lutz Bornmann, and Caroline S. Wagner, Generating Clustered Journal Maps: An Automated System for Hierarchical Classification