Re: displacement/spatial shift modeling??

Hi Stuart,

> I like your suggestion of using the examples/Rivers.java approach.
> However, a comment you made confuses me (see below)  You mentioned how to
> give the 'arrow' a visual direction by placing a square at the RP end, and
> that would use a SECOND flatfield.  If this is the case, what is the first
> flatfield?  In Rivers.java it appears to me that there is no flatfields at
> all, and no function types.

I should have said a second Data object. The first is the
UnionSet of Gridded2DSets for the arrow shafts, the second
is a FlatField ((row, grid) -> RP) that would put squares
at the RP locations as lazy-man's arrow heads.

> This also leads me to think, without a function type and flatfield for the
> 'arrows', any new arrow set on a display will require a
> removeReference/addReference pair??  Even though the FP points will be the
> same but the RP points will change, I will have to replace one Data with
> another??

The UnionSet and the FlatField would each have their own
DataReferenceImpl, so you'd have two calls to addReference().
But you can change the UnionSet and/or the FlatField without
the need for any new removeReference()/addReference() calls.

Good luck,
Bill