land area vs expanse

land area and expanse both are nouns.

Word	Noun	Adjective	Verb	Adverb
land area	Yes	No	No	No
expanse	Yes	No	No	No

As nouns, expanse is a hypernym of land area; that is, expanse is a word with a broader meaning than land area:

land area: an area of ground used for some particular purpose (such as building or farming)
expanse: the extent of a 2-dimensional surface enclosed within a boundary

Other hypernyms of land area include area, surface area.

land area (noun)	expanse (noun)
an area of ground used for some particular purpose (such as building or farming)	the extent of a 2-dimensional surface enclosed within a boundary
	a wide scope
	a wide and open space or area as of surface or land or sky