create envelope from multiple qqplot curves

Hi,

I have a number of qqplot curves from which I would like to create an envelope region that covers the area occupied by all of the curves.

I have tried using convhull but unsuccessfully,

say for example I have: x1=rand(1,10); y1=rand(1,10); qqplot(x1); hold on; qqplot(y1);

any idea on how to proceed to fill the region between the two curves?

Also: is there a way to store the Xdata and Ydata from the qqplot?

Thanks in advance

Answer 1

[José-Luis]

This will work if both datasets ( x1 and y1) have the same length:

data = rand(10,2);
x1 = data(:,1);
y1 = data(:,2);
h1 = qqplot(x1);
hold on;
h2 = qqplot(y1);
xData_x1 = get(h1(1),'Xdata');
yData_x1 = get(h1(1),'YData');
xData_y1 = get(h2(1),'Xdata');
yData_y1 = get(h2(1),'YData');

tempVal = max([yData_x1;yData_y1]);
yData_y1 = min([yData_x1;yData_y1]);
yData_x1 = tempVal;

patch([xData_x1 , fliplr(xData_x1)],[yData_x1 , fliplr(yData_y1)],'blue','FaceAlpha',0.5)