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

kindly help me to fill the diffrence with two diffrent colur in a x y plot as shown in the below example figure?

I need to shade postive(red color) and negative diffrences(blue color) in diffrent colors. Kindly give your suggesttions

t= 0:.01:1
AA = cos(t)
BB= sin(t)
diff = AA-BB
plot(t,AA)
hold on
plot(t,BB)
patch([t fliplr(t)], [AA fliplr(BB)], 'r')
hold off
%%% any suggestions Please!!

Answer 1

[Star Strider]

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.

[MS]

Dear star rider,

Thank you very much for the suggestions. I treid to use the same code for the data. But, i was not sucessful implementing the same to the data. I am attaching two data for your refernce. Would you mind to help me out in this?

D = load('Liftb60.mat');
DD = load('Liftpb60.mat');
wingArea = .5*1000*.01*(.3*.1);
t = 1/10000:1/10000:2;
figure
 AAA = -D.Lift_b/wingArea;
 BBB = -DD.Lift_pb/wingArea;
 t = 1/10000:1/10000:2;
 plot(t,AAA,'r','LineWidth', 6);
 hold on
 plot(t,BBB,'b','LineWidth', 6);
 Lv = AAA > BBB;                                                       % Logical Vector
patch([t(Lv) fliplr(t(Lv))], [AAA(Lv) fliplr(BBB(Lv))], 'm')
patch([t(~Lv) fliplr(t(~Lv))], [AAA(~Lv) fliplr(BBB(~Lv))], 'k')
hold off

[Star Strider]

Three changes:

t = (1/10000:1/10000:2).';                                                              % Must Be A Column Vector To Match The Data

and:

patch([t(Lv); flipud(t(Lv))], [AAA(Lv); flipud(BBB(Lv))], 'm', 'EdgeColor','none')      % Use ‘flipud’ & Vertical Concatenation For Column Vectors
patch([t(~Lv); flipud(t(~Lv))], [AAA(~Lv); flipud(BBB(~Lv))], 'k', 'EdgeColor','none')  % Use ‘flipud’ & Vertical Concatenation For Column Vectors

When I ran it with those changes, it produced what appears to be the correct result.

I do not completely understand your data, however the patch calls work.

.

[MS]

Thank you very much for helping me. It worked for me.

[Star Strider]

As always, my pleasure!