The StokesCoordinate is a poor fit to the Coordinate polymorphic model. You will probably find that if you try to use the Coordinate classes polymorphically, that StokesCoordinate will cause you to break the polymorphism. This means that concepts such as reference pixel, reference value, increment etc are meaningless for StokesCoordinate. You can recover these these attributes, but the functions to set these attributes have no effect. Relative pixel coordinates are defined.
All pixel coordinates are zero relative.
Another approach is to make an image type called Stokes. The length of whichStokes is the length of the axis, and the values define which stokes are in which axis value. Returns True if the conversion succeeds, otherwise it returns False and method errorMessage returns an error message. The output vectors are appropriately resized before use. Interconvert between world stored as a Double and world stored as a Stokes type.