Early map-makers used to draw terrain in pseudo-perspective in order
to convey the idea of rising and falling ground. As a technique it had some
advantages in that hills were immediately distinguishable from valleys, but
disadvantages in the degree of accuracy with which the different heights and
their horizontal location could be conveyed. This pictorial approach has almost
universally fallen into disuse, except for some city tourist maps that sometimes
depict landmarks in this way.
Given a table of values representing a terrain as heights above sea level,
what are the dependent and independent variables of this problem? What is
the usual representation of such data in
1. a rambler’s map of the countryside
2. a page in an atlas?