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Newbie questions about Edges & Nodes

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Newbie questions about Edges & Nodes

Postby nicomiceli » 11 Sep 2013 02:45

Hi All,

Sorry for the newbie questions but I really want to learn Gephi and need some help on the concepts.

I have a lot of cool ideas that I would love to use Gephi for but even after going through the wiki and tutorials I am trying to get my head around nodes edges, and sources, targets, IDs and all the stuff Gephi needs to build network graphs. Does anyone have any good resources or guides to network analysis (I already tried Google, but also want to see if this community has any hidden gems). I am taking a coursera class in October about social network analysis but want to get started sooner. :)

I work in internet marketing and have an example I would love some help with that I can use as a base for a couple ideas. Lets say I have 4 websites:
domain1.com - domain4.com and 7 links: linkA - linkG and I want to see how they are inter connected.

Attached is the raw data example and what I think the edges imports would look like. For the nodes import do I need to create a numerical ID row and would it be the full list of things, both edges and nodes?

Also if I want the site circles to be sized based on the amount of links would I have to weight them before I upload? (all my tests resulted in equal sized circles)

Thanks in advanced!

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Raw data example
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Posts: 1
Joined: 10 Sep 2013 02:41

Re: Newbie questions about Edges & Nodes

Postby pegerp » 11 Sep 2013 09:37

Hi Nico.

I recommend you take a look at VNA file format, https://gephi.org/users/supported-graph ... na-format/. You can open VNA files with Gephi.

For example your network could look something like:

Code: Select all
*Node data
ID name
1 domain1.com
2 domain2.com
3 domain3.com
4 domain4.com
*Tie data
from to strength
1 2 1
1 3 1
1 4 1
2 3 1
2 4 1
3 4 1

I did not test that example so if Gephi complains something try to fix it yourself by looking at what might be wrong.

If the network was undirected (which links are not!) those would be all the possible edges in the network. However that should give you an idea how easy it is to manually or with scripts to build networks. If some links were more important than others you'd use higher value in strength column.

Save that example as network.vna. Then open the file in Gephi (File > Open...) and go to Overview > Ranking > diamond shape (size/weight) > choose Degree from drop down menu > press Apply. This will change the size of the nodes according to degree that each node has. Because all nodes have the same degree they are the same size.

Using VNA format in my opinion is easier than using Data Laboratory's import CSV functionality. It is also possible to omit the *Node data completely and only define *Tie data section in the VNA. Gephi will automatically create the nodes that the tie data defines.

Good luck with your studies! :)
Posts: 101
Joined: 21 Dec 2011 18:10

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