I have to create an array having grid points and its co-ordinates in it ?

I have to create an array having three values (value,x-coordinate,y-coordinate) of the image named dMap. The following code I have been running but its not working.

Main file:

params.topRow=200;
params.topColum=330;
params.skipPoints = 5;
params.numberOfGrids = 10;
params.gridCollumns  = 20;
params.gridRows = 20; 
params.bottomColum=1;
dMap= imread('disp01.png');
[dMapRow, dMapColum]=size(dMap);
params.dMapColum=dMapColum;
params.dMapRow =dMapRow;
randomGrids=createRandomGrids(params,dMap);

Function File:
function [randomGrids]=createRandomGrids(params,dMap)
    numberOfGrids = params.numberOfGrids;
    gridCollumns  = params.gridCollumns;
    gridRows = params.gridRows;
    topRow=params.topRow;
    topColum=params.topColum;
    bottomRow=params.bottomRow;
    bottomColum=params.bottomColum;
    dMapColum=params.dMapColum;
    
    % heigth of a grid (region of interest)
    gridHeight = abs(topRow - bottomRow);
    
    % number of lines between the rows in the grid
    rowsBlockGrid = round(gridHeight/gridRows)-1;
    
    % By how much the width of the next row changes, relative to the previous row
    stepInc=abs((topColum-bottomColum)/(bottomRow-topRow));
    randomRowsNumbersAllGrids = cell(numberOfGrids,1);
   randomRowsNumbersOneGrid = zeros(gridRows,1);

    % Create an array of random numbers, used to select the rows in a grid
    for ii = 1:numberOfGrids
        for jj  = 1:gridRows
            randomRowsNumbersOneGrid(jj,1) = round(topRow + rowsBlockGrid*(jj-1) + rowsBlockGrid*rand);
        end
        randomRowsNumbersAllGrids{ii,1} = randomRowsNumbersOneGrid;
    end

    randomGrids = cell(numberOfGrids,1);
    randomGrid = zeros(gridRows*gridCollumns,3);
      
    % Create grids of points
    for ff = 1:numberOfGrids
        step=0;
        %Go through all rows in a grid
        for ii=1:gridRows
            
            % current row in the region of interest (the size changes as ROI
            % is a trapezium)
            currentRow=round(topColum-stepInc*step):round(dMapColum-topColum+stepInc*step);
            
            step=randomRowsNumbersAllGrids{ff,1}(ii,1)-topRow +1;
            
            % index of the current row in an image
            idx = randomRowsNumbersAllGrids{ff,1}(ii,1);
                
            % Copy spaced points from the image into a grid
            for currentCollumn=1:gridCollumns
                [~,currentRowSize] = size(currentRow);
                numberOfLinesBetweenGridRows = round(currentRowSize/gridCollumns);
                index = ((ii-1)*gridCollumns+currentCollumn);
                randomGrid(index,3) = currentRow(1,1)+round(numberOfLinesBetweenGridRows*currentCollumn);
                randomGrid(index,2) = idx;
                randomGrid(index,1)= dMap(idx,round(currentRow(1,1)+numberOfLinesBetweenGridRows*currentCollumn));
            end

        end
        randomGrids{ff,1} = randomGrid;
    end

end