How do I add scale markers to the legend, to indicate values for the sizes of points in a scatter plot?

Hello,

I have the scatter plot showing a 4 dimentional data set. It was generated using:

scatter(dimentionA,dimentionB,dimentionC,dimentionD,'filled','MarkerEdgeColor','w')

The x-y axis, cover 2 dimentions, the colourbar covers the 3rd and the point sizes cover the 4th dimention.

How do I add a point size/scale indicator to the legend, in order to lebel the 4th (point sizes) dimention?

Thanks!

Answer 1

[Bjorn Gustavsson]

I'd do something like:

sz = 12:2:24; % your suitable selection for your dimentionC-mapping-to-size
y4size = linspace(45,110,numel(sz));
x4size = 15*ones(size(y4size));
scatter(x4size,y4size,sz,'k','filled')
for it = 1:numel(sz)
  text(15.5,y4size(it),sprintf('%3.1f',Cval(it)))
end

You'll have to fill in your suitable range of values of your dimentionC-data that you want to display the size of the scatter-points for, and also change the 12:2:24 to something suitable. But this should give you something to start with.

HTH

[Hamid Attar]

Thanks for your answer. But I meant in the legend itself, not the figure (since I already have done essentially what you said for the figure). I meant something like the image attached here.

Ideally 5 intevals in the bounds of min(dimentionC) to max(dimentionC)

Thanks

[Bjorn Gustavsson]

Well, if you want them in something boxed, you could create an additional axes and plot the scatter-chart in that one - making it look like a legend.

You will also find some things on the file exchange: legend-scatter, velest2mat, and Bubble-scatter the first two show legend-style capabilities.

HTH

[Hamid Attar]

Sorry you are misunderstanding my question.

I don't want anything boxed.

I just want the marker size in the legend to correspond to the marker sizes in the plots

[Bjorn Gustavsson]

No, I do understand perfectly. You want a "legend" where you can give a key to the relation between the size of the scatter-markers and the quantity. You for some reason are tied to the idea that it has to be done with the function legend. That is not the case. In at least the 2 first FEX-links I gave you there were legend-for-scatter functionality, differently named, but with the functionality you requested. No one of your readers will know or care if you made the size-key with the legend-function or by some other mean, the legend is nothing but a small box with the key for what is what in the figure. You are allowed to make such a boxed key any which way you want - or need. In addition to the links I gave you there are a number of other legend-enhancements on the FEX.

[Hamid Attar]

Thanks a lot, I figured it out using the first link. Very helpful!

[Bjorn Gustavsson]

My pleasure.

The file exchange is GREAT, I've gotten so much useful stuff there that I've no idea how much time and effort I've saved through the years. My first step when solving a problem is to have a look there for a solution...