It is necessary in designing public structures to consider what can or cannot be seen from a specified building or other object, called the Source Object. In particular, an architect must consider the question of whether the Target Object is visible or obscured, depending on the desirability of seeing the Target Object. For example, an unobstructed view of a park may be desirable, whereas it may be preferable not to see a parking lot. A two-dimensional method is described below for determining the percentage of the Target Object that is visible from one side of the Source Object.