Is there a name for this type of sculpture?
Solution 1:
Many years ago my friends and I used to pore over local maps looking for potential ley lines. We'd select one for "on-site" investigation, then get out and walk along it - usually for several miles.
I was always struck by how often we were able to use footpaths, bridle paths, turnstiles, etc., and how often we encountered striking views across the landscape, and geodetic monuments.
geodetic monument - a stone or concrete pillar that marks a true place of trigonometric points.
Here's a Wikipedia page on the Peirce Geodetic Monument. Such points won't always offer a clear view to a notable landmark. But they're always precisely positioned in relation to something, so very often this will be the case.
Solution 2:
"Geodetic monument" does not apply to the viewfinder shown in the photograph. Unlike the archaeological (i.e., old and the consequence of human activity) monuments in the photograph, a geodetic monument is simply for designating the precise location of specific latitude-longitude and/or elevation coordinates. Nothing of the kind is visible or implied in this illustration. Such monuments were commonly erected during the surveys establishing boundaries, for instance: large enough to remain in place and to bear the carved or affixed coordinates of that location, but certainly not the mammoth features shown here.
I recommend "viewfinder" for this means of focusing the visitor's gaze upon the distance feature. I've never seen one during my extensive travels in the U.S. and Canada. How nice to see this rather than the coin-operated telescope that is common here.