function [flat_pos,flat_dir] = flatten_vecfield(Qposition,Qdirection)
absolute_upQ = floQ([0,0,1]);
upQ = Qposition.Qproject(absolute_upQ);
rightQ = absolute_upQ.Qcross(Qposition);
prj_dirQ = Qposition.Qproject(Qdirection);
prj_uplength = prj_dirQ.Qdot(upQ,'matrix');
prj_rightlength = prj_dirQ.Qdot(rightQ.normalize,'matrix');
flat_pos = cat(ndims(Qposition)+1,Qposition.azi,Qposition.elv);
flat_dir = cat(ndims(Qdirection)+1,prj_rightlength,prj_uplength);
end