hypsography

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The scientific study of the earth's topologic configuration above sea level, especially the measurement and mapping of land elevations.
• noun A representation or description of the earth's topologic features above sea level, as on a map.
• noun Hypsometry.

from The Century Dictionary.

• noun See the extract.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun sciences The data present in contour lines; measurement of altitude or depth versus area.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun measurement of the elevation of land above sea level
• noun the scientific study of the earth's configuration above sea level (emphasizing the measurement of land altitudes relative to sea level)