Net Explorer

Interactive network exploration widget.

Channels

Inputs

Network (Network)
Network object to plot.
Items (ExampleTable)
Alternative meta data to associate with network.
Items to Mark (ExampleTable)
A subset from items instances to mark.
Items Subset (ExampleTable)
A subset from items instances to hide.
Vertex Distance (SymMatrix)
Distance matrix containing distances between all vertices.

Outputs

Selected Network (Network)
Subnetwork of all selected nodes.
Selected Examples (ExampleTable)
Instances from items ExampleTable that corresponds to selected vertices.
Unselected Examples (ExampleTable)
Instances from items ExampleTable that corresponds to unselected vertices.
Marked Examples (ExampleTable)
Instances from items ExampleTable that corresponds to marked vertices.

Description

Net Explorer is used to visualize graphs, let the user explore them by selecting their individual parts and transmit the corresponding data to other widgets. It is currently available only in latest (Qt4) version of Orange.

To use Net Explorer from a python script one should also read orngNetwork Orange module documentation.

Classification Tree Graph
- Node Tab

Navigation

Four navigation buttons are located in the upper right corner in control area.

Zooming:

Zooming mode is selected by default. User can zoom in a rectangle by pressing and holding the left mouse button and dragging the mouse to draw a rectangle to zoom in to. Zoom out (one level) command can then be executed by pressing right mouse button.

Zoom to extent:

By pressing this button the zoom is automatically set to show all visible nodes in the network.

Zoom selection:

By pressing this button the zoom is automatically set to show all selected nodes in the network.

Panning:

Use this mode to drag the network around the canvas.

Marking and Selecting

The widget features a two-stage procedure for selection of vertices, which allows for a very flexible manipulation of subsets of vertices. Vertices can be marked and/or selected. Marked vertices are presented by filled circled and selected vertices are highlighted with a yellow border.

Vertices can be selected manually by clicking or by drawing selection rectangle. Selection mode is enabled by pressing fifth button from the top in the upper right corner in control area. Another way to select vertices is to add or remove the marked vertices to or from the selection, or to replace the current selection with the marked vertices (buttons seven to nine).

The vertices can be marked based upon values of the attributes of the corresponding objects. Most marking options are available in the Mark Tab.

Vertices Tab

Parameters in vertices tab govern the appearance of network vertices and data associated with them. User can select optimization method, vertex color and size attribute, set the labels and tooltips and other rendering options.

Optimization methods:

The user can specify the number of iterations of the optimization procedure where applicable.

Labels & tooltips

A number of attributes can be chosen to form vertex labels or tooltips. Font size can also be set.

Show labels on marked vertices only

When selected, only labels on marked nodes are displayed.

Inside view

In this special mode, only selected vertex and vertices closer to it than specified distance are shown.

Show missing values

Indicates whether missing values should be displayed ad questionmarks.

Edges Tab

Parameters in edges tab are used to specify the appearance of edges. One can set edges color, width and whether weights are displayed.

Explore vertex distances:

When selected, user can examine the distance between vertices that can be given through "Vertex Distance" signal. To display the distance, one must first select a vertex. When hovering over an arbitrary vertex, the distance between selected and the vertex under mouse pointer is displayed as a popup.

Mark Tab

Most options for interactive network exploration are gathered here. User can search for nodes by value in items meta data, mark neighbours of selected vertices or mark vertices by number of connections.

Complete list of marking features:

Info Tab

General information (such as: number of vertices, number of edges, diameter, clustering coefficient) about network are displayed here. To calculate and display degree distribution, click "Degree Distribution" button. Network can be saved in Pajek format clicking on "Save network" button.

Examples

The best way to get to know how to use this widget is by playing with it. Try some of the following network data sets:

More comprehensive list of examples will be available soon.