Expand and Collapse Groups of Vertices with NodeXL v.132

09SepMay 7, 2015 By Marc Smith

Clusters are now groups in NodeXL. Recently, the NodeXL team has been focused on a set of new features related to grouping sets of vertices together. In the previous version we released a feature that allowed all sorts of groupings to be recorded in the worksheet. What’s new is that the three clustering algorithms we have already provided are just one form of group, components (connected sets of vertices) are another, and user labeled sets are a third method of creating a group of nodes in NodeXL (this last feature is still pending). This release adds the ability to add vertices to a group and then collapse all of the vertices in that group to a metanode – a composite of all the nodes in that group. It is then possible to expand the collapsed vertices into the graph

These features are part of a larger effort to support time in which “time is but a group” – a set of nodes and edges present in a time slice. We are working on designs in which some groups are sequenced, allowing the user to move up and back through collections of vertices that may appear or disappear over different time slices/groups.

Here are the most recent features: 1.0.1.132 (2010-09-06)

After you group the graph’s vertices (NodeXL, Analysis, Groups), you can now select all the vertices in a group. Go to the Groups worksheet and click on a group name.
Once a group is selected, you can collapse it into a single vertex. Go to NodeXL, Analysis, Groups, Collapse Group. You can expand it again using Expand Group.
The Groups worksheet now includes a column that tells you how many vertices are in the group.
Bug fix: The NodeXL, Help, Check for Updates feature stopped working in version 1.0.1.131.
Bug fix: If you clicked NodeXL, Graph, Show Graph while editing a worksheet cell, you would get a message that started with “Unable to set the Hidden property of the Range class.”

1.0.1.131 (2010-08-19)

This version introduces the concept of “vertex groups,” or “groups” for short. A group is a set of related vertices. All vertices in a group are shown with the same shape and color. Clusters are an example of groups.
The worksheets that used to be called “Clusters” and “Cluster Vertices” are now called “Groups” and “Group Vertices.”
The NodeXL, Analysis, Find Clusters button in the ribbon has been moved to a new NodeXL, Analysis, Groups menu.
You can now group vertices by connected components, meaning that each group of interconnected vertices will have the same shape and color. Go to NodeXL, Analysis, Groups, Find Connected Components.
You can now group vertices using the values in a column on the Vertices worksheet — all vertices with degree greater than 100 in one group, all vertices with degree greater than 50 in another, for example.
If you open an older NodeXL workbook in this new version of NodeXL, the Clusters and Cluster Vertices worksheets will be automatically renamed.
You cannot open a new NodeXL workbook in an older version of NodeXL. If you attempt to do so, you will get a message that starts with “This document might not function as expected because the following control is missing: Clusters.”

Automatic for the people (who use the latest NodeXL!). Release v.1.0.1.128

08JulMay 7, 2015 By Marc Smith

The NodeXL team has just released a new version (v.1.0.1.128) that contains a new “Automation” feature that allows users to define a collection of operations to perform on their network graphs and invoke the complete set in a single button click AND reuse that configuration on other workbook graphs. In fact, the feature will apply the configuration you define to all the files you specify, allowing easy processing of large collections of network data sets.

This week the feature is partially complete. Users can invoke the merge duplicate edges, calculate graph metrics, auto-fill columns, create sub-graph images, find clusters and show graph. These operations can require as many as dozens of clicks when performed manually. If you have dozens or hundreds of network data sets the result is a daunting case of repetitive strain injury and carpal tunnel syndrome. Instead, with automation, these operations can be carried out orders of magnitude more frequently without much pain!

The next release will feature the complete package which will then include control over the layout and graph options. As a result, automatically generated network visualizations can be produced in a pipeline: users will be able to specify a query using the NodeXL desktop network data collector and then automate the processing of large collections of data sets.

The result should be better analysis of time series data sets that have many “slices”. The feature points the way to additional development work for supporting the comparison between networks to evaluate their evolution.

The REM album “Automatic for the people” takes its title from the motto of Athens, Georgia, eatery Weaver D’s Delicious Fine Foods.

Ordering smaller components in a graph – a NodeXL feature tip

12AprMay 7, 2015 By Marc Smith

From this:to this: in just a few clicks.

Many network graphs contain disconnected smaller graphs, called “components”, within them.

Most layout algorithms do a poor job of managing to group each component in a separate space. Instead, often, components are laid over one another, suggesting connections that are not real.

A simple solution we have implemented in NodeXL is to offer to sweep up all the smaller components in the graph and order them in neat rows at the bottom of the canvas. This feature was mentioned in a previous post, but finding the feature may not be obvious:

From the NodeXL network graph canvas toolbar, select the drop down menu next to the selected layout type.

This will display the following menu of layout choices and options:

Select the last option: “Layout Options…”

Which reveals:

Select the option: “Put the graph’s smaller components at the bottom of the graph“. This dialog also presents other options related to how long the Fruchterman-Reingold layout should calculate and how strong the parameter that governs the force that pushes nodes away from one another should be. You may find that changing these values improves the FR layout for your data.

Here is a graph that is mapped without the component ordering feature selected. Many components are scattered around the chart.

This image represents the connections among a population of Twitter users who mentioned the term “Cisco“. This chart was created using the Fruchterman-Reingold layout. It is noisy and messy given the nature of the graph it has to render.

The Harel-Koren layout option is better but has a significant flaw: all the isolates are jumbled on top of one another in that smear at the center of the ring in the upper left of the graph.

Here is the same graph created with the Harel-Koren layout with the added “Put the graph’s smaller components at the bottom of the graph” option selected:

All the many lightly connected Twitter authors are lined up in size order (size is mapped to the number of followers that user has in Twitter). This removes them from getting in the way of the “giant component”, the big connected group of Twitter users who both tweet the word “cisco” but also follow, mention, or reply to someone else who also mentioned the word “cisco”. The core of this group is visible along with some peripheral groups or people who both mention the company and talk to other people who do as well. The isolates mention Cisco but do not do so as part of a larger conversation (as seen at the time of this snapshot).

An additional tip: nodes are plotted on the screen in NodeXL in an order governed by the “Layout Order” column in the Vertices worksheet. If we use the “Autofill Columns” feature we can easily set the Vertex Layout Order to the same value to which Vertex Size was set. This has the effect of lining up the nodes by size, making a kind of histogram. All the singletons or isolates, the nodes with no connections to any other node, line up first, then the dyads, the triads, and the quads. Each larger sized component sorts from its smallest to its largest by the size of the largest node in the component.

Node and Venn: NodeXL can create Venn Diagrams!

27JanMay 7, 2015 By Marc Smith

NodeXL updated starting with version 1.05 with features that make it fairly easy to create basic “Venn Diagrams”. A Venn diagram is a familiar way to illustrate the overlap (or lack thereof) of two or more “sets” of things.

There are some very amusing Venn diagrams out there! This one in particular made me laugh but I may be dating myself.

The Venn diagram feature is a special request from the Microsoft Biological Foundation group.

A Venn is related to but different from an Euler diagram. An “n-Venn” diagram is a collection of closed curves (“circles”) on a plane where all the circles intersect. A “simple” Venn diagram has just two circles but complex diagrams can have more. A 2 circle Venn diagram has 3 regions (A, B, A+B) and a 3 circle Venn diagram has 7 regions (A, B, C, AB, AC, BC, ABC).

A Survey of Venn Diagrams can be found at http://www.combinatorics.org/Surveys/ds5/VennEJC.html.

Our implementation is a bit of a hack, we basically let you define the X/Y location of 3 circles. A richer Venn tool would make it easy to take set data and define these circles. We may get that implemented in the coming months.

M	T	W	T	F	S	S
		1	2	3	4	5
6	7	8	9	10	11	12
13	14	15	16	17	18	19
20	21	22	23	24	25	26
27	28	29	30	31

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