hypsography vs hypsometry

hypsography and hypsometry both are nouns.

Word	Noun	Adjective	Verb	Adverb
hypsography	Yes	No	No	No
hypsometry	Yes	No	No	No

As nouns, hypsography and hypsometry are synonyms defined as:

hypsography and hypsometry: measurement of the elevation of land above sea level

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