Identify location of the 2D grid data

Hi

I have this data and have transformed it into 2D [X, Y].

rectList = [...
    1 1 1 1
    1 2 1 1
    1 3 1 1
    1 5 1 1
    2 1 1 1
    2 2 1 1
    2 5 1 1
    3 2 1 1
    3 3 1 1
    4 5 1 1];
xRange = [ min( rectList(:,1))  max( rectList(:,1))];
yRange = [ min( rectList(:,2))  max( rectList(:,2))];
allX   = xRange(1):deltaX:xRange(2);
allY   = yRange(1):deltaY:yRange(2);
[X, Y] = meshgrid( allX, allY);

Is there to identify logical index of X,Y that belongs to original point, rectList. so it looks like

locOri = 
[1 1 0 0
 1 1 1 0
 1 0 1 0
 0 0 0 0
 1 1 0 1]

Thanks much

Answer 1

[Bruno Luong]

rectList = [...
    1 1 1 1
    1 2 1 1
    1 3 1 1
    1 5 1 1
    2 1 1 1
    2 2 1 1
    2 5 1 1
    3 2 1 1
    3 3 1 1
    4 5 1 1];
deltaX = 1;
deltaY = 1;
xRange = [ min( rectList(:,1))  max( rectList(:,1))];
yRange = [ min( rectList(:,2))  max( rectList(:,2))];
allX   = xRange(1):deltaX:xRange(2);
allY   = yRange(1):deltaY:yRange(2);
[X, Y] = meshgrid( allX, allY);

locOri = reshape(ismember([X(:),Y(:)],rectList(:,1:2),'rows'), size(X))

locOri = 5x4 logical array
   1   1   0   0
   1   1   1   0
   1   0   1   0
   0   0   0   0
   1   1   0   1

[Pete sherer]

thanks much

Answer 2

[Shashi Kiran]

Hi @Pete sherer,

To identify the logical index of points in the X,Y grid that correspond to the original points in rectList, you can follow these steps:

• locOri is created as a logical matrix of the same size as X and Y, initially set to false.

% Initialize locOri as a logical array with zeros
locOri = false(size(X));

• For each point in rectList, find where X and Y match the current point’s coordinates in rectList. Then update locOri to true at those indices.

% Loop through each point in rectList and set corresponding locOri entries to true
for i = 1:size(rectList, 1)
    % Find the indices in X and Y that match the current rectList point
    xMatch = X == rectList(i,1);
    yMatch = Y == rectList(i,2);
    % Set locOri to true at positions matching both x and y
    locOri = locOri | (xMatch & yMatch);
end
disp(locOri)

   1   1   0   0
   1   1   1   0
   1   0   1   0
   0   0   0   0
   1   1   0   1

This output has 1s at positions that correspond to the points in rectList and 0s elsewhere, as expected.

Hope this helps.