Hi Bernhard,

What I do not yet understand, is why there are two dimension parameters. If
this can indeed be used with different source and target dimensions, then I
think the documentation should explain what happens if the dimensions are
unequal, because I cannot think of a "standard" behaviour for that.

Yep, I seem to remember having seen that in the code - it's possible and valid to have a 2D and a 3D point. Not sure how it's handled, Barend can probably explain. Barend, given such a usage is quite infrequent maybe we can make the 2nd one optional? (i.e. equal to the first one by default)