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Visualizing and Editing Graphs

Revision as of 08:22, 26 April 2011 by Jan-frederik.wigger.bfr.bund.de (Talk | contribs) (Step 3. Saving the graph)

Visualizing and Editing Graphs (Under Construction)

STEM uses graphs as data structure to save information concerning population sizes, areas, spatial information, neighborhood of areas etc. When you start a scenario, you get the information of its appendent graphs in a visual form, e.g. when you see the outlines of the countries you included into you scenario.

The Graph Editor offers the possibility to visualize graphs without starting a scenario. You can get an overview of the data and edit titles, the size of the area, add populations or adjust geographic information of a node.

Step 1. Open the Editor

When you right-click on an item of the type "Model" within a project of the STEM Explorer, you'll see a context-menu that offers you to display the canonical graph of all graphs that are contained under this model. When you right click on a bottom-level model, you can display the canonical graph of all graphs that lie under this selected model. When you right-click on a selected single graph under your models or in the graphs folder, you'll be able to open the graph editor for this graph file.

Step 2. Editing the graph

The nodes of the graph are small circles, where the color shows the membership to one subgraph, i.e. when you have opened a canonical graph consisting of several countries, the country nodes will have different colors. When you click on a node (provided the graph contains nodes with spatial information, otherwise nothing will be shown in the display) you get information about its title, its URI and all labels that are assigned to this node. You can move the nodes by keeping the left mouse button pressed and drag the node to your desired location. When you want to add a label to a node (e.g. add information about population size or area of the node) you must select one node by left-clicking on it and open the context menu with a right click. You can then add a population or area label and edit the values in the bottom part of the editor.

Edges can also be selected. Information about the class of edge and potential edge values are shown in the bottom part of the display.

Step 3. Saving the graph

When you want to save the edits you have made, you can select "Save" (and the changes are saved into the same files) or you select "Save As" where you have to select a folder and filename. When you were working on a reference to graphs in the STEM graph/model repository, local copies of the references including your changes will be saved to your workspace. If you were working on local copies already, your files will be overwritten, when you select "Save Graph".