I have seen a few poles that have two identical signs, facing opposite directions and at an angle (as if they were meant to be seen from altitude). Each sign has three digits, with the third as a superscript as if the number was meant to be from 0.0 to 99.9.
One sign is pretty much at the end of an airport runway, and another is about 10 miles north and could be aligned so that a plane going to/from that same runway could see it, so it’s possible that it has something to do with that, although I can’t find any reference to runway distance/direction signs that look like that anywhere.
I see signs somewhat like that in a lot of places, often along rural or semi-rural roads. In general, I have no idea if there are airports anywhere around. They do look like they are intended to be viewed from an aircraft, but they don’t look like any serious kind of navigation aid. I wonder if they are some kind of surveying marker.
There has been some commotion in part of the San Francisco area when the local utilities company pretty much demanded that everybody should leave the ground above a pipeline clear of trees (I assume the company would cut them down at its own expense) to make aerial inspection and actual access to the pipelines easier.
I have had people try to build their house over a 16" high pressure natural gas line.
Not a very good idea and manys peoples goes out to read to them from the book.
Also we would get fired if we got caught that high ( 200’ ) while on patrol. You can get a nose bleed way up there. Can’t see much from that far away. Oil field gathering systems were usually done, clear of the trees and/or up to 50’ above ground.
OKAY, that was puffed up a bit, add 20’ to the altitudes I first said.
Turkey farmers will shoot at you if you’re not at least a 500’ away.
A lot of companies have painted fence posts at the edges of the roads. Color coded so they can be positively identified.
