Area under a shape?

Hello, I'd really like to know how to calculate the area beneath a shape like this:

So from the outer borders to x-axis. Since the values are repeating I reckon trapz() doesn't work.

Answer 1

[KSSV]

Read about polyarea, convhull.

https://in.mathworks.com/help/matlab/ref/convhull.html

convhull gives you coordinates of the points which defines your shape, with these corodinates youc an use polyarea.

https://in.mathworks.com/help/matlab/ref/polyarea.html

[Niklas Kurz]

Thank you for you answere at first.

Yea, I used a similar code to calculate the area of the shape:

b = boundary(Xp,Yp)
X0=Xp(b); Y0 = Yp(b)
A = polyarea(X0,Y0)

Surprisingly (kind of) this works as well with

k = convhull(Xp,Yp)

The thing is, I want to compute the area under the figure, not inside. My formulation was a bit ambiguous. Sadly I couldn't yet find an answere to this issue here.

[KSSV]

Pick the curve you want to find area under and use trapz.

[Niklas Kurz]

I thought there'd be a more elegant solution like with

area(Yp,Xp)

I can cast the shadow of the shape, but nothing more.

Well, I keep it simple and extract a curve manually as u advised. This works at the least.

[Niklas Kurz]

If u need some inspiration: This User has answered the question sophisticatedly:

https://de.mathworks.com/matlabcentral/answers/565277-how-to-apply-a-fit-on-this-shape?