Most of conversion / Analysis, the output of the function and method can be stored in the Dataset with the "spectrum" DataArray. For example, - [ ] convert_to_kspace: * "band" - [ ] derivative, maximum_curvature, minimum_gradient * "derivative_n", (n is derivative order), "max_curv", "min_grad" - [ ] Normalized functions. - [ ] filters (analysis/filters) - [ ] deconvolution On the other hand, plotting functions the arg should be xr.DataArray, to avoid confusion.