How can I carve out a region of a 3D matrix given a specific x and y range?

I'm looking analyze a specific area of a 3D data set, and the size of the area needs to be based on the ground sample distance and the number of detectors in the x and y direction of the focal plane:

nx = 600; % # of detectors in x direction

ny = 600; % # of detectors in y direction

GSD = 2; % Whatever GSD in m

x = -GSD*nx/2:GSD*nx/2;

y = -GSD*(ny -1)/2:GSD*(ny-1)/2;

Is there a way I can apply x and y to a x, y, z matrix of data?

Answer 1

[Epsilon]

Hi Wbenn7,

To access a region of a 3D matrix based on two dimensions only, pass a colon operator ‘:’ as the third index to access all the data of the third dimension within the range of the first two dimensions.

Example:

% Provided  dimensions
nx = 600; 
ny = 600; 
GSD = 2;  

data = rand(nx, ny, GSD); % Example data matrix
xRange=100:200; % range definition
yRange=200:300; 

extractedData=data(xRange,yRange,:); % To extract a given range

for x = xRange
    for y = yRange
        for z = 1:GSD
            data(x, y, z) = x + y + z; % To apply data to a given range
        end
    end
end
overwrittenData=data(xRange,yRange,:)

Please refer to these documentations for further reference:

Array indexing: https://www.mathworks.com/help/matlab/math/array-indexing.html

Multidimensional arrays: https://www.mathworks.com/help/matlab/math/multidimensional-arrays.html

Hope it helps!

[wbenn7]

Thank you very much!!