This initialization is expensive: https://github.com/NCAR/DART/blob/59b75b716f761b447382bb0fe59044bbb9c2275d/assimilation_code/location/threed_cartesian/location_mod.f90#L1319 3D sphere: https://github.com/NCAR/DART/blob/59b75b716f761b447382bb0fe59044bbb9c2275d/assimilation_code/location/threed_sphere/location_mod.f90#L1449
