The Isovist_App can be used to estimate the minimal connected series of locations required to give complete visual coverage of a space. Known as the ‘minimal set’, the resulting set of nodes and edges is a precursor to a true spatial graph. 

To find a minimal set:

• Set up a drawing and open the isovist analysis menu as normal.
• Select the ‘find a minimal set’ option at the foot of the menu
• Using the cursor, click at the desired ‘root’ location of the minimal set. Doing so defines an origin for the estimation process to begin from.
• Wait… the process of estimating a minimal set should be visible on screen as a sequence that gradually generates nodes (rings) and edges (lines). The nodes are scaled relative to their importance in the minimal set structure.
• Clicking again in an alternate location will restart the estimation from the new root point. 
• To increase or decrease the accuracy of the estimation, edit the slider provided. Increasing accuracy slows the estimation process.
• To hide the minimal set results, toggle the ‘find a minimal set’ option off again.

Above: Finding minimal set candidates in Kahn’s Fischer House