1.  hypsography(n = noun.cognition) - the scientific study of the earth's configuration above sea level (emphasizing the measurement of land altitudes relative to sea level);
is a kind of geology

2.  hypsography(n = noun.act) hypsometry - measurement of the elevation of land above sea level;
is a kind of measure, measurement, measuring, mensuration

hypsography, n. a description or mapping of the contours of the earth's surface.

Derivative:
hypsographic adj. hypsographical adj.