utopographer
One who describes a utopia.
Mr. Plantagenet-Buchan knitted his brows. "Utopographer? Or was it a Utopologist? Or Utopolitan? Not a bad word, Utopolitan. No—it was Utopographer. I read it in one of the weeklies downstairs, the Spectator or the Nation or the Saturday. We might lead the talk rather carelessly towards Utopias and see what happened."
Where it comes from
Blend of utopia + topographer, probably coined by English writer Herbert George Wells (1866–1946) in his 1927 novel Meanwhile: The Picture of a Lady: see the quotation.
Adapted from the Wiktionary entry utopographer (CC BY-SA 4.0).