online journal maps extended with the Social Science Citation Index 2003

Loet Leydesdorff loet at LEYDESDORFF.NET
Tue Jan 11 04:40:01 EST 2005

** apologies for cross-postings
Dear colleagues,

I extended the possibility to map journals online with the 1710 journals
included in the Social Science Citation Index 2003.

 <> Social Science Citation Index
2003 citing (1710 journals)
 <> Social Science Citation
Index 2003 cited

 <> Science Citation Index 2003
citing (5907 journals)

 <> Science Citation Index 2003 cited

The files can also be accessed from

One can make maps from these files without further programming by importing
the files into Pajek. Pajek is a visualization program (freeware) available
at :

1. Click on the journal name of interest; save the file as .txt file
2. Open Pajek; read the file under File > Network > Read; first set the
"files of type" to all file-types (*.*)
3. Draw the picture; select, for example, under Layout > Energy >
4. Return to Pajek for changing parameters or use the Options for coloring
and resizing the pictures; the pictures can be exported as bmp.

All files are so-called cosine matrices (Salton & McGill, 1983) with cosines
included insofar as cosine ?  0.2. One can raise this threshold within Pajek
by using Net > Transform > Remove, etc. (The threshold value of 0.2 may low
for the Science Citation Index.) The input files can also be edited with an
ASCII text editor.

I intend to write a short manual shortly. Please, feel free to feedback.

With kind regards,


Loet Leydesdorff
Amsterdam School of Communications Research (ASCoR)
Kloveniersburgwal 48, 1012 CX Amsterdam
Tel.: +31-20- 525 6598; fax: +31-20- 525 3681
 <mailto:loet at> loet at ;

 <> The Challenge of
Scientometrics ;  <> The
Self-Organization of the Knowledge-Based Society

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