Extending Binary Qualitative Direction Calculi with a Granular Distance
  Concept: Hidden Feature Attachment
  In this paper we introduce a method for extending binary qualitative
direction calculi with adjustable granularity like OPRAm or the star calculus
with a granular distance concept. This method is similar to the concept of
extending points with an internal reference direction to get oriented points
which are the basic entities in the OPRAm calculus. Even if the spatial objects
are from a geometrical point of view infinitesimal small points locally
available reference measures are attached. In the case of OPRAm, a reference
direction is attached. The same principle works also with local reference
distances which are called elevations. The principle of attaching references
features to a point is called hidden feature attachment.
