Chapter 5. Tutorials

Table of Contents

1. First Step
First graph display
Save options
Algorithms
2. Improving a layout
Introduction
File-system importation
Using other Layouts :
Showing Labels
Showing a specific kind of file.
Conclusion
3. People in InfoVis
Analyzing an author.
What, if any, are the relationships between two or more or all researchers

1. First Step

In this part, the goal is to help you to simply make a graph and to save your work.

First graph display

Importation of a graph

  • Select the File->Import item.

  • Select a method of importation : Grid approximation, for example.

Do not modify the default parameters. Here is displayed the graph with nodes (red) and edges (black). With the wheel of the mouse, you can zoom on the graph to see a specific node. In moving the mouse with its left button pressed, you can translate the graph in the plane of the view, pressing the key SHIFT for rotation and the key Ctrl (Alt key on Mac) to rotate around the z axis and zoom. In order to come back to the oldest view, Select View->Center view from the menu bar.

  • Select Algorithm->Measure->Misc->Id from the menu bar, to compute a value (metric) for each node and edge of the graph.

The graph is now displayed with colors depending of the metric. You can change the colors with the menu : Algorithm->Color->Metric Mapping. This plugin computes an interpolation between the two selected colors.

Creation of a graph

In this section, we learn how to create its own graph, element by element.

  • Select the File->New from the menu bar to create a new graph.

  • Create a graph adding nodes and edges. For a node, select the mouse toolbar operation and click on the position you have chosen. To insert an edge, select the mouse toolbar operation. Click on the source node, then on the target node. You can display or hide them with Edges checkbox in the Overview subwindow. In the same way, you can display or hide the arrows checking Arrows.

  • Delete elements of the graph. Select the mouse toolbar operation, then click on the element you want to delete.

Save options

To save your work, you just have to select File->Save or Save as: a dialog appears allowing to enter the author of the graph and some comments; then after clicking on the 'OK' button, just type the file name and choose its location.

The second way to make a save is to export the graph in a special format : GML or TLP (equivalent to Save as). Select File->Export and the format of your choice, then choose the file name and location.

Algorithms

This part explains how to apply an algorithm to a graph. Previously, you have created or imported a graph. Select Algorithm->Layout (for example) and an algorithm : Hierarchical->Hierarchical Graph for example.

In this case, we use an algorithm dealing with the layout of the nodes and the edges. It is possible to apply all other kinds of algorithm. Some layout algorithms may not apply to your graph if it does not belong to the right category of graphs. With the Bubble Tree layout, you can not display a grid. If it is not valid, a pop-up message will displayed explaining the problem.