An Egocentric Reference System for Affordances

This article suggests a theory of egocentric reference systems for human observations of affordances that can be used to semantically account for human observations on the web. Based on the perceptual theory of affordances, which suggests that human perceive the potential actions the environment affords, an egocentric reference frame is established. This egocentric reference frame takes the observing agent as its datum. The theory is completed with transformations that allow to project values of observed affordances from one user’s reference frame into another user’s reference frame. The potency of the theory to account for the semantics of human observations is demonstrated through the implementation of an egocentric reference system for the prototypical affordance of hikability that a mountain path affords to a hiker, using user-ratings from a community driven web portal.