Extracting data from a matrix in slanted rectangular form

i have data consisting of x, y and z . I want to extract data from the above matrix in a slanted rectangular shape( If I joined the vertex values of rectangles it will be slanted and there are 4 x values and 4 y values ). The image shows the contour of the data I want to extract the data in the rectangle as shown in the figure (Thick bordered).

thank you

Answer 1

[KSSV]

clear all
[X,Y,Z] = peaks(100) ;   % data 
% the slant rectangle I picked
rect = [
   -1.5000    0.1399
   -0.2005    1.6968
    1.0300   -0.1224
   -0.6014   -1.2770
   -1.5000    0.1399
] ;
figure ; surf(X,Y,Z) ; view(2) ; hold on ; plot(rect(:,1),rect(:,2),'b') ; 
% get the indices of piints which are inside the rectangle 
id = inpolygon(X(:),Y(:),rect(:,1),rect(:,2));
% initilaize the required matrices 
Xi = NaN(size(X)) ;
Yi = Xi ;
Zi = Xi ;
% fill the values inside rectangle 
Xi(id) = X(id) ;
Yi(id) = Y(id) ;
Zi(id) = Z(id) ;
figure ;surf(Xi,Yi,Zi)

[Abhilash K S]

Thanks, KSSV . I got it One more question not exactly related to this how can I convert back my matrix to xyz format, the value of z is unique for particular x and y the figure shows the pattern of my data

I need it to convert back to x,y,z format after some processing

[KSSV]

If X is a matrix, you can convert it to array x by X(:).

[Abhilash K S]

Thanks

[Saurabh Agarwal]

From this inclined matrix (as rectangle is inclined) is getting. How to make a straight matrix from this?