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Brian, Yes, I don't think it is a problem with the color scale. This may be a subtle contouring artifact where the contouring algorithm is drifting into areas in shouldn't, if you see what I mean. This is something you would never notice except in these two-tone scenarios. (I would continue experimenting with the contouring parameters rather than the color table at this point.) Can you explain to me how you are deriving DTdy? I am curious how other plotting packages handle these data. Best, Unidata IDV Support > I wonder if it is a matter of having only 6 colors in the table? > > No, I made it more (still half red, half blue) using the + in the color table > editor, and changed the range, and the contours are still woozy purplish. > So it is not some color-interpolation thing I think. > > > > On Jan 20, 2016, at 6:44 PM, Unidata IDV Support <address@hidden> wrote: > > > Brian, > > > > Thinking about this a bit more, I don't believe there is a bug or problem > > here. > > > > The color table is being displayed in exactly the manner you wish. In > > particular, where you are seeing "blending" are areas where values in the > > contour data are actually going back and forth across zero and therefore > > are mixed > > purple. It is not the colors that are blending, it is the data themselves > > across > > the "zero boundary". > > > > Another way of looking at this is choosing a two tone black and white color > > table. The white will fade into the background. You will see grey as the > > data > > approach either side of zero. > > > > Do you buy this theory? :-) > > > > Best, > > > > Unidata IDV Support > > > >> Same issue when I import this new table. > >> Contours are not uniform red or blue, but mixed purple. > >> Thicker contour line width helps show it. > >> > >> [cid:3EC5425C-85EE-4B22-87E4-1F10BC1A1C6C] > >> > >> > >> > >> > >> > >> On Jan 20, 2016, at 3:16 PM, Unidata IDV Support > >> <address@hidden<mailto:address@hidden>> wrote: > >> > >> Brian, > >> > >> It is not that the colors are bleeding, it is your color table that > >> appears to > >> be discreet, but apparently is not. Remove all other displays and you will > >> see > >> what I mean. I am unfortunately having trouble loading your bundle though > >> I did > >> get it to load once where I was able to come to that conclusion. > >> > >> Try the attached color table which I believe is actually discreet. > >> > >> Best, > >> > >> Unidata IDV Support > >> > >> > >> > >> See how some of the contours are purplish? The color bar is purely > >> blue/red . > >> > >> Is it a bug, or something we have to live with? > >> Small .zidv bundle attached along with screenshot. > >> > >> Brian > >> > >> > >> > > > > Ticket Details =================== Ticket ID: WAX-506623 Department: Support IDV Priority: Normal Status: Open