Fill in the region between two line curves.

Hi,

I need to fill the region of two lines by 'hatched grey' color. I used the following code:

M = [0.54, 0.7, 0.74, 0.78];
X1 = [0.007856, 0.008394, 0.008607, 0.012584];      %X1 values
X2 =  [0.007901, 0.008461, 0.008739, 0.011302];      %X2 values
xq = (0.54:0.000001:0.8);   %adding intervals to make line smoother
X3 = interpn(M,X1,xq,'pchip');  %other type: pchip, makima, spline etc.
X4 = interpn(M,X2,xq,'pchip');  %other type: pchip, makima, spline etc.
set(0,'defaulttextinterpreter','latex')
figure(1)
hold all; 
plot(xq, X3,'r-','LineWidth',1.5);
plot(xq, X4,'b--','LineWidth',1.5);
X=[xq,fliplr(xq)];           %create continuous x value array for plotting
Y=[X3,fliplr(X4)];           %create y values for out and then back
fill(X,Y,'color',[17 17 17]);    %plot filled area
xlabel('X','FontSize',12); % Label the x axis
ylabel('Y','FontSize',12); % Label the y axis
axis([0.5 0.8 0.007 0.013]);

However, when I tried to make the line smoother, the fill in command didn't take place! I need to keep the line smoother and fill the region with a 'hatched grey' color at the same time.

Any help will be appreciated.

[Walter Roberson]

Your lines cross. You need to find the interesection and plot only within the shared area.

[~, idx] = min(abs(X3-X4));

Now use only 1:idx as the portion to fill inside.

[Rahman]

Thank you.

Answer 1

[Image Analyst]

"Any help will be appreciated." <== See the FAQ: https://matlab.fandom.com/wiki/FAQ#How_do_I_shade_the_region_between_two_curves.3F

[Rahman]

Thank you.