How to set scatter plot colors in order to adjust all plots to a same reference?

Hi all,

I am intending to define the color of my scatter plots based on the same reference for "zaxis", lets suppose [8*10^-5,8*10^-3]. The code that I applied just changed the scale of the color bar, but did not change the color on the plot. I would like to change the colors of the plots to values higher than the [max(z), min(z)] and also to do another plot based on values lower than the max and min. To sum up, the scatter plot have exhibited just max and min colors automatically.

I tried

    % 
      axis manual
      axis([min(position), max(position), min(depth), max(depth), 8*10^-5, 8*10^-3,8*10^-5, 8*10^-3])
      colorbar

and also

      % 
        colorbar
        caxis([ 8*10^-5 , 8*10^-3])

I tried other intermediary values between "min and max" and higher than "min and max", but the representation of the plot still reconfigured to the min and max.

Thank you for your time,

Answer 1

[Mike Garrity]

I'm not sure I'm following. Let's take a simple, concrete example:

rng default
nval = 100;
cmin = 8e-5;
cmax = 8e-3;
c = cmin + (cmax-cmin)*rand(1,nval);
x = randn(1,nval);
y = randn(1,nval);
scatter(x,y,[],c,'filled')
colorbar

At this point, caxis returns

ans =

     0.000174264390450   0.007767094831544

Because those are the min & max values in the array c. If we do this:

caxis([cmin, cmax])

Then the colorbar and the mapping the scatter uses to go from the array c to color values stretches to make room for the entire range.

That's kind of hard to see because the range is small. If we move one of the limits way in, it becomes more obvious.

caxis([cmin, cmax/2])

Notice how all of the scatter values in the top half of the range are now drawn in the yellow color at the top of the colormap. Is that different from what you've encountered, or did you expect something different?

[Ryan Alicea]

Hi Mike,

I am trying to do something similar as this to a series of scatter3 plots, however, adjusting the caxis limits has no effect on the scatter colors themselves, only the text appearing next to the colorbar. Do you have any idea as to why this could be? Here is an example of my process. I am using R2017a.

Q_nrml = Q/max(limit);
[~, sortIndexes1] = sort(Q_nrml);
C = jet(length(Q_nrml));

 figure(1)
scatter3(X(sortIndexes1), Y(sortIndexes1), Z(sortIndexes1), 15, C, 'filled');

colormap(C)
caxis([min(limit) max(limit)]);
c = colorbar;

The color of the data is still scaled according to itself instead of the limits set by caxis. caxis is only changing the labeling of the colorbar, not the plot itself.

Thank you!