Hello everybody,
I'm plotting the derivative of pressure (mmHg/s) against the pressure itself (mmHg) in MATLAB and the result is a circle with few lines in the edge. The question is: how can I calculate the Area inside this circle?
I am attaching a figure with a illustrative example
Thanks in advance!
http://in.mathworks.com/matlabcentral/fileexchange/10579-closed-area-calculation/content/f_closed_area.m
Hope this helps.
Rhenan,
Have you tried using the formula to compute the area of an irregular polygon?
A= | 0,5 * ( SUM [ ( (Xi + Xi+1) - 2 * Xmin) * (Yi - Yi+1) ] ) |
Just add your first coordinate point to the end of the list to close the loop.
How about using limits of sums the same way as Riemann integration? You can also go into numerical integration formulae... Newton Cote's formulae to be precise. http://en.wikipedia.org/wiki/Newton%E2%80%93Cotes_formulas (Simpson's rule should work fine for you)
The easy way, is using the command polyarea(X,Y).
http://www.mathworks.com/help/matlab/ref/polyarea.html
Thank you, all of you, very much for the support. It is exactly what I was looking for!
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