Handle topography on antenna position and core position on input generation #142
Description
Currently input generation in done in cartesian coordinates, using the x,y of the antennas, and flat ground.
We need to be able to set them following the current topography, and adjust the core porsition to where it intercepts the ground.
Zhaires can handle negative altitudes, as long as internal shadow routine is off and altitude does not go below sea level.
alternatively, antennas must be above a virtual ground altitude, set at the altitude of the lowest antenna.
Ask reconstruction people how they treat core position. Is int flat or topographic. Does it have flat or round earth?