After using contourf(X, y, z, 5) to draw contours in matlab, how to calculate the area less than a certain value (or the area between two contours)?

[X Y Z]= peak value; % generate a two-dimensional Gaussian distribution surface to replace your data.

[c h]=contourf(X，Y，Z，5)； Save the returned c h when extracting%.

Hc=get(h,' children'); % Get isoline filling object

N = length (HC);

V = zero (n,1);

S = zero (n,1);

For i= 1:n

x=get(hc(i)，' xdata ')； The% i-th filled object x data

y=get(hc(i)，' y data ')； Y data of the% i-th filled object

L = length (x);

s(i)=sum((x([2:l， 1]) - x)。 *(y([2:l， 1])+y))/2； % Calculate the area of the i-th filled object

v(i)=get(hc(i)，' user data ')； % Get the equivalent value corresponding to the ith object

end

[v m n]= unique (v); % Find objects with the same value

s=accumarray(n，s)； % spell out their area together

V stands for equivalent isoline.

S represents that the area surrounded by isoline is larger than this equivalent part.

I think you finally want to find the area between two equivalents.

Therefore, you can find an area larger than a certain value and an area smaller than a certain value.

For several sentences returned by matlab itself, it is relatively simple to find an area larger than a certain equivalent value.