> what happens at themoment is that the code draws each layer of the stack
> sequentially and as soon as it stacks data onto top of unknown data the data
> can not be visualized anymore ... 
> 
>     known 1   -> paints OK
>     UNknown 2 -> contains *UNKNOWN* (will not paint)
>     known 3   -> will not paint either because it should paint starting
>                  from the *UNKNOWN* value not painted in 2
> 
> opinions ... ?
> 

To start the discussion:

The stacking is just a nice way to visualize things, it is especially
useful if the value of #1 > #3 at one time and the opposite another time.

The amount of #3 is known, just as #1 is. Therefore it should be graphed.
We're not starting #3 on top of #2 but on top of all data. I see it as
stacking on the Y axis in stead of stacking it on the Z axis (as normal
AREA over AREA is).

One counter argument could be that the current behaviour shows that
something failed, I disagree with this in advance as it doesn't work
when the last value would be unknown... (a zero would show the same)

It is for above arguements that I think this is a technical issue that
should be overcome. The fix as described by Tobi will work but is just
that: a fix.


The second way of handling this, make all values unknown, could also be
valid. This could be useful for instance when the data is related closely
such as troughput and errors on an ethernet. If you have not all of the
data, you have no information at all. This is why I mentioned it.
IMO it is better to actually draw unknown data (in nice bright red) at
the whole Y range. We would need a value meaning 100% and this could be
made by putting a VRULE at each graph time that has unknown data.


Regards,
Alex

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