Re: Reversed axes and connect the dots?

Hi John,

> Q1:In oceanography it's customary to have a "reversed" axis for depth.
> For example, a 2D plot of some measured value (like salinity) ert to
> depth, the origin of the Y axis is at the top of the axis and
> represents the surface of the ocean. Depth increases down the axis
> rather than up from the cartesian origin. Is there any way to tell
> VisAD to draw a reversed axis?

Then you said:

> I also tried reversing the max and min for the axis using
> setRange but that didn't work either--the data points
> disappeared and the axis showed the usual orientation.

visad/examples/Test26.java uses repeated calls to setRange()
that reverse axes back and forth, demonstrating that the basic
technique of 'setRange(max, min)' does work to reverse axes.
There must be some other problem.

> Q2: I have succeeded in producing 3D scatter plots where the plot
> symbol is colored by another measured variable. Is there a way in VisAD
> to connect the plotted points with a line segment? If so, can the line
> segment also be colored by the color variable?

To connect the points you need to supply a topology
(i.e., which points are connected) which you would do
via a Gridded3DSet with manifold dimension = 1, which
you would probably use as the domain Set of a FlatField.
Note that this is no longer a scatter plot, though. Now
your data would have a MathType like ((x, y, z) -> v)
and ScalarMaps x -> XAxis, y -> YAxis, z -> ZAxis and
v -> RGB.

Cheers,
Bill