In Postgis 2.1.1, I have a line in 3 dimensional space connecting two antenna points on the earth's surface. Is it possible to create an ellipse around that line? I have a formula to compute the radius of the ellipse at any given point along the bisecting line.
The ellipse is described as the Fresnel zone in this article: http://en.wikipedia.org/wiki/Fresnel_zone
I feel like I need some kind of 3D version of ST_PROJECT. ST_PROJECT allows me to plot an approximation of this ellipse on its side, but I need the ellipse to be oriented such that the bottom half lies between the bisecting line and the earth, below it.
It would be simple if I could form the bottom of the ellipse by modifying just the Z coordinate of points running along the bisecting line, but this isn't quite correct because one antenna is taller than the other, causing the line to slope.