How to calculate double integral of a circular area?

I only have three matrices, X, Y and A as attached. X and Y are the discrete point position in the Cartesian coordinate, A is the corresponding value of each point. All of those three matrices are 64×180 format (64 radial and 180 azimuthal points within a circular area).

Is there any way to calculated the bulk A value in this circular area?

I can understand the double integral in a rectangular area, as shown in this question (https://ww2.mathworks.cn/matlabcentral/answers/464644-double-integral-of-numerical-data), but it's really out of my knowledge for a circular area.

Answer 1

[Hiro Yoshino]

You may want to use the indices:

radius = 0.5;

idx = sqrt(X.^2+Y.^2) < radius;

This way, you can extract the elements of A within the radius.

[Xinchen Zhang]

Sorry forgot to say, the A value is not centrosymmetric circular area, even it is not well-regulated. So I might need a double integral to solve the result of bulk value.