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Other software for overlaying Google Maps:


·       Science mapping of cities, institutes and collaboration networks

(Leydesdorff & Persson, 2010);


·        Topcities

(Bornmann & Leydesdorff, 2011);


·       Using Scopus data

(Bornmann, Leydesdorff, Walch & Ettl, 2011);


·       Indicating excellence using integrated impact (I3) (July 2011)


·       Make Google Maps of USPTO Patents (Oct. 2011)

Paj2KML for generating (Pajek) network overlays to Google Maps


Paj2KML uses a 1-mode pajek file (.net) with geographical encodable labels for generating a .kml file that can be used as an overlay to Google Maps. The program also generates input to the GPS Visualizer which allows one to websites under Google Maps with different node sizes and link weights. The input format is extremely flexible since one can write one’s own labels; for example, using the concatenate function in Excel.


1.     Save the Pajek network file as .net file using the default in Pajek; use a DOS-based file name (≤ eight characters);

2.     Use the labels for the geo-encoding, for example, at http://www.gpsvisualizer.com/geocoder/ . (One can enrich the content of the labels with postcodes for more precise geo-coding; geo-coding can be done automatically using the Sci2 Tool available at https://sci2.cns.iu.edu/user/download.php. However, note that my programs assume the format of gpsvisualizer for the input.)

3.     Save the results file by cutting and pasting it from the window into a simple (DOS-) file; for example, “geo.txt”;

4.     Store the Pajek .net-file, the geo-information (geo.txt), and the program the same folder;

5.     Run the program which prompts you for file names and generates “citycoll.kml”, inp_gps.txt, and pajek.net as output files.

a.     The file citycoll.kml can be read by Google Earth or uploaded at a web server and read with Google Maps. At http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=http:%2F%2Fwww.leydesdorff.net%2Fgmaps%2Fcitycoll.kml&sll=37.0625,-95.677068&sspn=50.644639,79.013672&ie=UTF8&z=2 one finds an example of a resulting file.

b.     The file inp_gps.txt can be made input to the GPS Visualizer at http://www.gpsvisualizer.com/map_input?form=data; see at http://www.leydesdorff.net/maps for further instruction on how to generate a website from this information; This is the best option!

c.     Pajek.net repositions the nodes at their geo-coordinates; see also at http://www.leydesdorff.net/maps for further instruction.


The output files can be changed with an ASCII editor (such as NotePad). For example, one can change the color of the lines or the shape of the icons.


Note that the labels have to be of such a format that they can be geo-encoded. For example in the above file:


*Vertices 45

  1 "Amsterdam, Netherlands"                 0.0000    0.0000    0.5000

  2 "Arlington, USA"                         0.0000    0.0000    0.5000

  3 "Beijing, Peoples R China"               0.0000    0.0000    0.5000

4 "Berlin, Germany"                        0.0000    0.0000    0.5000


If the size of the nodes is indicated with the x_fact and y_fact parameters in Pajek, this information is also used in the output files for Google Maps; the weights of the links (edges; arcs) are used proportionately for the width of the lines.


Amsterdam, 31 January 2010.