Welcome to this video.
This video offers
an introduction
into the software
tool VOSviewer.
My name is Nees Jan van Eck.
I work as a researcher
at the Center
for Science and
Technology Studies
of Leiden University
in the Netherlands.
My research focuses
on the development
of tools and algorithms mainly
for analyzing the structure
and dynamics of science.
Together with my
colleague Ludo Waltman,
I have developed VOSviewer.
VOSviewer is a powerful
tool to analyze
the structure of
scientific fields.
To tool can, for example, be
used to analyze and visualize
different types of
biometric networks.
In this video, I will show
how you can use the tool
to analyze your own
data sets, and how
you can create your
own visualizations.
But first, I will show
how to run VOSviewer.
Using a browser or my computer,
I go to the VOSviewer website,
VOSviewer.com On this website, I
click on the Download web page.
From this web
page, VOSviewer can
be downloaded for
different systems.
I'm working on the
Windows system,
so I will choose to download
VOSviewer for Windows.
A zip file will be
downloaded, and it
will be saved in my
Downloads folder.
I go to my Downloads folder,
and I unpack the downloaded zip
file.
VOSviewer can now
simply be launched
by executing the
VOSviewer.exe file.
After VOSviewer
has been launched,
we enter the main
window of the tool.
To give you an overview of
the main functionalities
of VOSviewer, I will
open an example map
that is distributed
with the tool.
We can open the VOSviewer
files as well as Pajek files.
In this case, I specify
a VOSviewer map file
and a VOSview network file.
And I click on the OK
button to open the map.
The map that we have
opened is a co-citation map
of journals in the fields
of economics and management.
Each circle
represents a journal.
The size of each journal
indicates the activity
of the journal measured
in terms of publications.
The distances between
the journals in this map
are also important.
In general, the smaller the
distance between two journals,
the higher the number
of co-citations.
That means the higher the
number of publications
in which two journals
both have been cited.
In this way, closely
related journals
are located close to
each other in the map.
We can also make the co-citation
links between the journals
feasible.
For example, the 400
strongest co-citation links.
Colors represent groups
of related journals.
In red, we see journals from
economics; in pink, finance
and accounting; in green,
management and business;
in yellow, marketing; and in
blue, operations research.
VOSviewer has zoom and
scroll functionality
that can be used to explore
maps in full detail.
For example, you may be
interested to inspect
the economics journals
in more detail.
By zooming in, more and more
journal names become visible.
Different visualization
features are available.
I will show a few of them.
It is possible to increase
the size of all journals.
The relative size of
journals can also be changed.
Frames instead of
circles can be shown.
The background color
can be changed.
Also, a density visualization
instead of a network
visualization can be shown.
This visualization
provides a quick overview
of the most important
areas in a map,
and the density can also
be shown for each cluster
separately.
VOSviewer has also
search functionality.
So for example, we can search
for the American Economic
Review journal and see where
it is located in a map.
Until now, we have looked
at an existing map.
But using VOSviewer, you can
also create your own maps.
For example, maps can
be created directly
based on data downloaded
from the Web of Science
[inaudible] database.
I will show how this works in
the case of Web of Science.
I will first demonstrate
how to download data
from Web of Science.
In my web browser, I
go to WebofScience.com.
Here, I change all
databases into "Web
of Science Core Collection."
For this demonstration, I
will collect all publications
from the Journal of the
Association for Information
Science and Technology that have
been published in the last 10
years.
So I enter the name
of the journal.
I enter the time periods.
And then I click Search.
That turned out to be
2,099 publications.
On this page, we see the
first 10 publications.
Unfortunately, we cannot
download the data of all
publications at once.
There is a limit of downloading
500 publications at the time.
For my data set, it means that
I have to download five files.
To save the data of the first
500 publications in a file,
I choose the Save to
Other File Formats option.
Here I enter 1 to 500.
Choose the Full Record
and Cited References
option and the
Tab-delimited option.
The plain text option
can be chosen, as well.
Then I click "send."
The data of the first
five hundred publications
will be downloaded in a file and
stored in my Download folder.
Offline, I have
repeated this process
for all of the publications.
So now, I have downloaded
five files in total.
To create a map based on the
data that I have downloaded,
I click, in VOSviewer,
on the Create button.
To get an overview of
the topics discussed
in the publications
in my data set,
I can, for example,
first create a term map.
To do this, I have to specify
the files based on this,
I want to create a term map.
Here, I select Web of Science,
and I select the five files
that I have just downloaded.
In the next step,
I specify that I
want to extract the terms
from titles and abstracts.
Now in the background, all terms
are identified and extracted
using natural language
processing techniques.
I choose the default
counting methods.
In the next step, I
increase the minimum number
of occurrences of a
term from 10 to 12.
In the next step, non-relevant
terms will be excluded.
So for example, terms with
a very general meaning.
In the last step, we see
a list of selected terms.
For each term, we see
the number of occurrences
and the relevance score.
And if necessary, we can
manually exclude terms.
Here we see the
resulting term map.
Each circle now
represents a term
from the titles and abstracts
of the publications in our data
set.
The terms are located
based on the co-occurrences
in the titles and abstracts.
The higher the number of
co-occurrences of two terms,
the closer they will
be located in the map.
If you look at
the colors, we see
that the journal for which we
have collected the publications
publishes on three main topics.
In green, we see terms like
publication, indicator, index,
citation, journal.
So terms on the topic
of bibliometrics
and scientometrics.
In blue, we see terms
like document, algorithm,
information, text,
search engine, query.
So terms on the topic of
information retrieval.
And in red, we see terms like
experience, person, interview,
perception,
information behavior.
So terms on the topic
of information sciences.
Apart from a term map,
also other types of maps
can be constructed based
on Web of Science data.
Now we have an overview
of the different topics
in our data set, it is
maybe interesting to show
how a co-citation map
can be constructed
based on the same data set.
To do so, I have to select
downloaded files again.
In the next step, we can
choose between different types
of analysis.
I select Co-citation
and Sources.
In all other steps, I will
use the default settings.
And this is then the
resulting co-citation map.
I can rotate the map to make
it somewhat better visible.
First of all, we see
that our focal journal
is located in the
center of the map.
Furthermore, we see,
in yellow, journals
that publish on the
topic of bibliometrics
and scientometrics.
In blue, we see
library journals;
in red, management journals;
and in green, computer science
journals.
A screenshot of this map
can be saved as a file
or copied to the clipboard.
The map itself can
also be saved by saving
the map file and
the network file.
By clicking on
the manual button,
the manual VOSviewer will
be opened in a web browser.
In the manual, you'll
find more information
on the functionalities,
but also, for example,
information on the file formats.
Finally, on the
VOSviewer website,
you will find sources to
get started with a tool.
Here, you will find
a book chapter that
provides a step
by step tutorial,
a paper in which VOSviewer
was originally introduced,
and a manual.
On the Publications page,
you will find references
to technical publications
on VOSviewer,
but also references to
application publications.
If you have any
questions or comments,
then you can always contact me
or my colleague Ludo Waltman
by using the Contact form.
This is the end of this video.
Thank you for
watching, and I hope
VOSviewer will be
useful for you.
