Clarification on Coordinate Systems

[bvanderbeek]

Perhaps @danielpeter or someone can confirm for me the global and local coordinates systems used by specfem globe. Only the global coordinate system seems to be briefly described in the manual...or maybe it is the local (Appendix A). I've attached an illustration of how I think things are oriented. Of particular importance to me is knowing which directions x1-, x2-, and x3- correspond to for elastic tensors in the global vs. local coordinates (I'm trying to read in fully anisotropic mantle models). If the illustration is correct, it may be useful to add to the manual.

Thanks for the help!
Brandon

specfem_globe_coordinate_systems.pdf

[bvanderbeek]

Ok, so my understanding of things has changed. Attached is a revised view of what I think the global and local coordinate systems look like.

[bvanderbeek]

Final figure update. I think there are three relevant coordinate systems that are now illustrated in the figure below (global, local geographic, and radial). For the mesh, elastic tensors should be provided in global cartesian coordinates but can also be supplied in radial and then rotated via the subroutine 'rotate_tensor_radial_to_global'.