MATLAB: Different colors for scatter plot points based on the difference of x-y values

colors

Hello,

I have a scatter plot of two arrays, x and y. I need to distinguish the points in the plot with different colours based on the difference between x and y values. Hope someone can help me!

Thanks very much

Best Answer

You will need to come up with a vector that contains the values you want to use to set the color of the points. Once you have that, pass it in as the 4th input using the following syntax:

scatter(x,y,sz,c)

See this example for more.

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How are the values of the lines stored? In two vectors containing Y values to the the same X coordinates? If so:

match = (y_blue <= y_red);
Area  = cumtrapz(y_red(match) - y_blue(match))

MATLAB: X-y plot: how to shade the difference between two lines in multiple colors

Correct idea, not quite the correct approach.

Try this:

t= 0:.01:1;
AA = cos(t);
BB= sin(t);
Lv = AA > BB;                                                       % Logical Vector
figure
plot(t,AA)
hold on
plot(t,BB)
patch([t(Lv) fliplr(t(Lv))], [AA(Lv) fliplr(BB(Lv))], 'r')
patch([t(~Lv) fliplr(t(~Lv))], [AA(~Lv) fliplr(BB(~Lv))], 'g')
hold off

producing:

.This uses ‘logical indexing’ to separate the two regions.

The independent variable (‘t’ here) may need greater resolution for more complicated curves for this approach to work correctly. If the curves are data, use linspace to create the indpendent variable vector with greater resolution, and interp1 to interpolate the data to it.

Best Answer

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