Therefore if a location has a large visual field will pick up a lot of points to sum, so initially it might seems controlling. However, if the locations it can see also have large visual fields, they will contribute very little to the value of control. So, in order to be controlling, a point must see a large number of spaces, but these spaces should each see relatively little. •
Controllability is a measure proposed by Turner (2001) that picks out areas that may be easily visually dominated. For a location it is the ratio of the total number of nodes up to radius 2 to the connectivity. Therefore on a controllable point, the area of visual field is small compared to the area viewable on the points it connects to.
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