MATLAB - best way to dynamically update a line handles' XData and YData?

Question

I am collecting data and plotting that data in real time. The data are produced by a motion capture system. I have one class DynamicDataset that is just a wrapp

Answer 1

The amount of data you're handling in each update, is large (although only a single point is actually changing), making your code O(N^2).

By using a second lineseries to build up a large group of data, you can alternate between adding every point to a short "active" line, and infrequently adding large blocks to the main lineseries. While this doesn't exactly avoid O(N^2), it lets you reduce the constant significantly.

If you do this, remember to overlap the "old" lineseries and "active" lineseries by one point, so that they connect.

Essentially:

    function updatePlot(obj, propNum)
        X = get(obj.LHactive(propNum), 'XData');
        Y = get(obj.LHactive(propNum), 'YData');

        X(end+1) = obj.(dynProps{propNum}).newestData(1);
        Y(end+1) = obj.(dynProps{propNum}).newestData(2);

        if numel(X) > 100
            Xold = [get(obj.LH(propNum), 'XData'); X(2:end)];
            Yold = [get(obj.LH(propNum), 'YData'); Y(2:end)];
            set(obj.LH(propNum), 'XData', Xold, 'YData', Yold);

            X = X(end);
            Y = Y(end);
        end

        set(obj.LHactive(propNum), 'XData', X, 'YData', Y);
    end