plot y Vs. X in heat-map plot

Hi all,

How can I create a scattered heat-map? I tried to find an already build function but I couldnt make it work for some reason.

[darova]

Can you be more specific? Are you trying to plot color line? Can you show something?

[sani]

I'm trying to color a scatter plot by the data density. something like this picture:

Answer 1

[darova]

Try this

x = rand(1000,1);
y = rand(1000,1);
R = 0.1;                        % circle radius
D = pdist2([x y],[x y]);        % create combinations of distances
C = sum(D<R);                   % how mayn points inside circle
scatter(x,y,10,C,'fill')
colorbar

Answer 2

[Cris LaPierre]

Heatmap accepts inputs of xvalues and yvalues. You may also specify a color variable.

However, I don't know that I'd consider heatmaps a y vs x plot. If that is what you want, perhaps consider using scatter, which allows you to specify a size and color for your pairs.

There is also gscatter if you want to color your data by groupings.

[sani]

Hi Cris,

I'm trying to present the density of one variable in respect to the other. I used scatter, but I wanted the points in the plot will colored differently where the data is more dence.

do you know a way to do it?

[Cris LaPierre]

We have a geodensityplot function, but that expects lat/lon for x/y. If you have a way of representing the density numerically, you could use that number to color your data using gscatter, or to create contour levels with contour or contourf.

If you don't want to reinvent the wheel, you can also find some solutions in the file exchange. A quick search found these two:

1. Data density plot
2. densityplot(x,y,var​argin)

You can also find some other approaches in this MATLAB Answer post as well as this one. It appears histogram2 or histogram3 are common solutions for this.