Converting a table to a matrix based on coordinates
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Hi,
I have a table which contains 3 variables: X coordinate (X), Y coordinate (Y) and a value in point (Int). X and Y coordinates are equally spaced. I want to convert it to a matrix, in which the position of an Int value in the matrix will represent its coordinates. How to do this?
Thanks in advance
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Accepted Answer
chicken vector
on 2 Jun 2023
Edited: chicken vector
on 2 Jun 2023
Be careful because Matlab uses inverted indeces so this way you have X as rows and Y as columns.
Just invert the indeces in the loop to invert this behaviour.
% Setup table for example:
x = 0:.1:.5;
y = 0:.2:1;
z = 0:5;
T = table(x', y', z', 'VariableNames', {'X', 'Y', 'Value'})
Now we extract some information about X and Y coordinates.
If your X and Y are in the form:
1:10
Then this part is not required.
% Initialise conversion:
nData = size(T,1);
matrixData = zeros(nData);
xStep = diff(T{[1,2],1});
yStep = diff(T{[1,2],2});
xOffset = xStep - T{1,1};
yOffset = yStep - T{1,2};
Finally we loop over the each row of the table to move the values in the matrix:
% Allocate table's values:
for j = 1 : nData
xMatrix = int64((T{j,1} + xOffset) / xStep);
yMatrix = int64((T{j,2} + yOffset) / yStep);
matrixData(xMatrix, yMatrix) = T{j, 3};
end
This is the result:
% Display result:
matrixData
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