I need to generate large polygons that are all on the same plane but are all some relative distance from the ground. I need to do this without knowing what the absolute altitude is.
So imagine I am generating a circle polygon. I would like to be able to say, "all points of this polygon are plotted with an altitude of 10 m relative to the center of the circle."
Is there any way to do this without looking up the absolute altitude of the point at the center of the circle? If I use relativeToGround as the altitude mode, I get a circle where each of the points making up the circle are 10 m off the ground underneath them. This looks bad, because I am stacking the circles and this means that the polygons tend to intersect in weird ways that are ugly.
The problem with setting them as absoluteToGround is that if I make it "10 m" then in some places that is inside the ground (if it is above sea-level) and in some places it is too high in the air (if it is below sea-level).
One idea I had was, is there a way to say, put the polygon on some kind of layer, and then make the layer relative to the ground? Probably not. Or is there any way to set an altitude relative to other some other entity (e.g., create a point with a relative altitude and then set all of the other points as absolute to that)? Again, I don't see any reason to think KML supports this, but I'm not a KML expert.
Are there any workarounds? I only found one other question on this topic and it is from sufficiently long ago (6 years) and with not that many answers or views (and not on the GIS forum) that I thought it was worth asking again.