Hi John, Actually, you can choose the colors: select the Z axis, then the color scale page and click New or Duplicate. You can build your own custom color scale.
Hope this helps, Jean Le samedi 13 novembre 2021 à 08:31 -0700, John Denker via gnumeric-list a écrit : > Hi Folks -- > > The Colored XY plot feature has the potential to be extremely > useful. I can give you a long list of important use-cases > if you want (see e.g. below). > > Right now it is marginally useful. The main drawback is lack > of control of the Z axis, i.e. the color. Different Z values > result in different colors, but the mapping from Z value to > color is undocumented and inscrutable. > > The documentation for Colored XY plots, in its entirety, says: > > > 10.3.4. Colored XY Plots > > > > Work in Progress > > Reference: > > https://help.gnome.org/users/gnumeric/stable/sect-graphs-overview-types.html.en#sect-graphs-overview-types-coloredxy > > Suggestion: It would be great if the Z axis would accept *strings* > like this: > "#00ff00" simplest case: solid green > "#00ff0040" green at 25% opacity > "#ff0000,#0000ff" red outline, blue fill > > Users who want to plot numerical data can construct their own > colormap consisting of an array of strings, then apply the > offset() function. > > Once the dust settles, it would be nice to document the > Colored XY plot feature. > > ============================ > Here is one use-case among many: > > Suppose we have a QAM64 modem. There are 64 possible codes > that could be sent, each with an X,Y value. At the receiver > we would like to plot the data. The X,Y position is given > by the voltages as received (including noise), and the color > is determined by what the symbol was /supposed/ to be. That > way we can see where the category boundaries are. We can > see to what extent a given symbol is encroaching on another > category. > > It would be unsatisfactory to implement this as 64 separate > XY plots for multiple reasons. First, that would be grossly > laborious. What's worse, if the red plot is in front, that > would put *all* the red points in front, which is not what > we want. Instead, we want the Z-order to be determined by > the order in which the symbols were received. > > =============================== > Additional remarks: > > *) Do not let the perfect be the enemy of the good. I can > happily live without the following creeping features. > > *) Creeping feature: > > "#ff0000,#0000ff,3,5.5" red outline, blue fill, shape 3, size 5.5 > > This would allow the marker shape (circle, square, diamond, > ...) to be determined on the fly, and also the marker size. > > This would allow a Colored XY plot to do everything a Bubble > plot does, and more. > > *) I'm not sure, but I wonder whether it might be better to > put the information in 4 columns rather than in a single Z > column. That is, separate columns for outline color, fill > color, marker shape, and marker size. Hmmmm. > > *) Creeping feature: > > As for the lines, as opposed to the symbols: Let the line > segment from point 1 to point 2 be a linear gradient, sweeping > from the point-1 color to the point-2 color. Anybody who wants > uniform-color segments can plot two points at each X,Y location > (ending-point and re-starting-point). > > *) Creeping feature: > > One could imagine other strings, perhaps X11 color names > such as DarkGoldenrod4, or perhaps SVG color names (which > are inconsistent with the X11 names) ... but for my purposes > names would be less useful than hex strings. I can compute > the hex strings as a function of the data using dec2hex(), > but I can't compute the names. > > I suppose the names are harmless, and they will appeal to > casual users (as opposed to power users). However, they > are neither necessary nor sufficient. They are not a viable > substitute for the hex strings. > > ========================================= > > So, how hard would it be to implement color-strings? > > Does anybody have any better ideas along these lines? > _______________________________________________ > gnumeric-list mailing list > gnumeric-list@gnome.org > https://mail.gnome.org/mailman/listinfo/gnumeric-list _______________________________________________ gnumeric-list mailing list gnumeric-list@gnome.org https://mail.gnome.org/mailman/listinfo/gnumeric-list
