Calculating the area of a plot, e.g convhull

Good day all, i am currently facing a problem where i cant compute the accurate area of my graphs. The problem is i have a data of 240 records and there are numerous shapes and i am supposed to consolidate all their areas, l have managed to get the area by using the convhull code however it is not accurate enough. Please help.

The below following is one of the examples that i need help:

The picture on the left is the convhull and computed area in matlab however i only want the area on the right. So is there a universe code where they will just take whatever shape there is and just compute the area under the curve as i have various shapes below as well.

Really appreciate it if there are some advices given as i really need some help here. l have also attached the three data files and my codes for reference.

close all; clear all; clc;

filename = 'o1-1.txt'

deliminator = ' ';

A = dlmread(filename, deliminator, 14, 0);

A = wdenoise(A,5, ...

'Wavelet', 'db5', ...

'DenoisingMethod', 'Bayes', ...

'ThresholdRule', 'Soft', ...

'NoiseEstimate', 'LevelIndependent');

resistance = A(:,1);

reactance = A(:,2);

delre = max(resistance) - min(resistance);

delim = max(reactance) - min(reactance);

L = sqrt(delre.^2 + delim.^2);

alpha = atan(delim./delre)*180/pi;

xc = resistance;

yc = reactance;

[k, av] = convhull(xc,yc);

plot(xc,yc,'*')

hold on

plot(xc(k),yc(k))

Answer 1

[Steven Lord]

Consider using an alphaShape instead of a convex hull since your shape isn't convex.