Plots interpolate to invalid points
This issue was created automatically from an original Mantis Issue. Further discussion may take place here.
The Plot Over Line filter creates a special column in its output called vtkValidPointMask that is a flag to the plot view to specify that the given point has no data and therefore should not be drawn. When the point is invalid, the rest of the columns are filled with zero for no particular consequence since these values will not be viewed. (Should they have NAN instead?)
The problem is that in the XY plot when you have a valid point next to an invalid point, it interpolates between the valid point. This creates inappropriate lines to the 0 axis. To see this problem in action, do the following.
- Load disk_out_ref.ex2, load Temp variable, Apply.
- Note that the range of Temp goes from 293 to 913. This is in Kelvins, so it never gets near zero.
- Plot Over Line. Apply.
The default line for the plot starts outside the mesh, goes inside, back outside, back inside, and then outside for a final time. This is reflected by the two distinct regions in the plot. However, notice that at the ends of each contiguous region there is a line drawn down to 0. Those lines should not be there. The data never goes to 0 and therefore we should not be drawing lines to 0.