elevation - What's the difference between hypsography and topography?

I've recently come across some data that has been labeled "hypsography". I looked it up and it sounds like topography. But this data source has data labeled "topography" separate from its "hypsography". What's the difference?

I've read the wiki for 'Elevation' and its starting to sound like all the "topos" I've been reading are really "hypsos"

Answer

Hypsography concerns the land's elevation, altitude or height above sea-level or some other reference surface. (Hypso is derived from the Greek Ύψος for height.)

Topography concerns physical and cultural features of the land and so includes hypsography, hydrology, the built environment, major boundaries, communication channels, etc. (Topo is derived from the Greek Τόπος for place.)

Note, however, that North Americans often (incorrectly) use "topography" when they mean only "elevation" (or "hypsography").