terminological obscurity

[Peter Hansen]

Mel Wilson wrote:

>    Depends on the coordinate system.  If the bases are east,
> north and up, then you're right to disagree.  If they're
> east, up and future, then you're also right although the
> argument is subtle.  If they're height, weight and Nielsen
> Rating, then A may be the best answer.

What's the inherent difference between the (east, up, future)
coordinate system and the (height, weight, Nielsen Rating)
one that makes the argument subtle in one case, but wrong in
the other?

-Peter