  When considering perceptions, the observation scale and resolution are
closely related properties. There is consensus in considering resolution as the
density of elementary pieces of information in a specified information space.
Differently, with the concept of scale, several conceptions compete for a
consistent meaning. Scale is typically regarded as way to indicate the degree
of detail in which an observation is performed. But surprisingly, there is not
a unified definition of scale as a description's property. This paper offers a
precise definition of scale, and a method to quantify it as a property
associated to the interpretation of a description. To complete the parameters
needed to describe the perception of a description, the concepts of scope and
resolution are also exposed with an exact meaning. A model describing the
recursive process of interpretation, based on evolving steps of scale, scope
and resolution, is introduced. The model relies on the conception of
observation scale and its association to the selection of symbols. Five
experiments illustrate the application of these concepts, showing that
resolution, scale and scope integrate the set of properties to define any point
of view from which an observation is performed and interpreted.
