Extracting data from a matrix in slanted rectangular form

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Abhilash K S 2017-2-8

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https://ww2.mathworks.cn/matlabcentral/answers/323908-extracting-data-from-a-matrix-in-slanted-rectangular-form

评论： Saurabh Agarwal 2021-7-6

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

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采纳的回答

KSSV 2017-2-8

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https://ww2.mathworks.cn/matlabcentral/answers/323908-extracting-data-from-a-matrix-in-slanted-rectangular-form#answer_253821

在 MATLAB Online 中打开

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)