Automatically generate the time step value from image dimensionality and order of the equations
Is there any real value in allowing the user to template over the scalar type? Perhaps it should always be double, unless there's a compatibility problem with the Point class.
Derive this class from TransformBase class. Currently, this class derives from AffineTransform, although it is not an affine transform.
Add a figure in the documentation that informs the formulas used in this class that are used to transform Cartesian to azimuth-elevation-radius
Support vector images
It's not yet clear how multi-echo images should be handled here.