Creating Desire Plots

In order to start, and visualise, Desire Line Diagrams, you first need to set up one or more Desire Plots. A Desire Plot is a data object that enables you to choose a unique colour for the Entity journeys you wish to track in a Desire Line Diagram. It also enables you to filter which journeys to track. The filters you can choose comprise one or more attributes from 'Entity Type', 'Final Destination', 'Origin' and 'Target'. For example, if you want to view the journeys of all Entities leaving your model through the 'West Exit', you would select this Exit under 'Final Destination'; if you wanted to view the journeys of all Entities entering from 'Street Entrance 1', you would select this Entrance under 'Origin', and so on.

This procedure assumes that you have opened LEGION Simulator and loaded model and data files.

To create a Desire Plot:

Click or select Analysis > Start Desire Line Diagram Generation.
The 'Edit Desire Plot' dialog is displayed.
Click New to add a new Desire Plot to the left-hand list.
Type a meaningful name for the Desire Plot in the highlighted name box and press Enter.
On the 'Desire Plot' tab, choose a unique colour by selecting one of the two options:
- User defined – select a colour from the adjacent drop-down list.
- By Entity Type–select one of the colours already associated with one of your model's Entity Types from the adjacent drop-down list.
The colour you select here will become the colour of all Entity trails tracked in the Desire Line Diagram.
Click on the 'Entity Filter' tab.
If you have already created Named Filters, which you would like to use, select the 'Named Filter' option and choose a filter from the drop-down list. You can now click OK to finish and save your filter settings. If you do not have any Named Filters, either create them as described in "Creating Named Filters" in Model Builder, or continue with the next step.
From the drop-down list labelled ‘Filtering Method’, select one of these two options:
- Selected attributes – you can now define further filtering criteria
- None – no attributes will be selected (this is equivalent to switching the Desire Plot 'off'
If you chose Selected attributes, select one or more attributes from the four categories of ‘Entity Type’, ‘Final Destination’, ‘Origin’ and 'Target'.
To do this, expand the tree of ‘available’ attributes as you need and move them into the ‘selected’ pane using the > and >> buttons (to remove selected attributes, use < and <<).
If you have selected more than one attribute in the previous step, the 'Logic method' drop-down list becomes available. From this list, select one of the following:
- AND – only Entities with every selected attribute will be selected
- OR – Entities with any of the selected attributes will be selected
Click Apply to save your settings (you can now add more Desire Plots) or OK to save your settings and close the dialog.
The new Desire Plot object is created and listed in the Object Directory. Like other data objects in the Directory, you can deactivate them and reactivate them by toggling the white tick on and off.
To add more Desire Plots, repeat from step 2.