How to find maximum vertical distance between reference line and a curve?

Hi,

I have plotted curve and reference in one graph. I wanted to find the maximum distance between two the line and coresponding x value.

I have used this code.but my answer is not coming right, so can you please help me . I am also showing the graph.

X=e.X;

Y=e.Y;

plot(X,Y);

hold on;

x=e.x

y=e.y;

plot (x,y);

[M,I] = max(abs(Y-y));

display([M,X(I)]);

[Fangjun Jiang]

Is there an error message? The code looks right, except for a case where Y is a row vector but y is a column vector. Then there would be no error but the result is out of whack.

Answer 1

[DGM]

Something like this:

% sample vectors don't share the same x-positions or length
% assuming both x vectors are monotonic increasing
x1 = [1 2 3 4 5];
y1 = [1 2 3 4 5];

x2 = [1.8 3 3.6 4.5 5];
y2 = [3 3.2 4 4.3 5];

% these are the sample locations in the overlap region
xs = unique(sort([x1,x2]));
xs = xs(xs>=max(x1(1),x2(1)) & xs<=min(x1(end),x2(end)));

% calculate distances, maximize
y1f = interp1(x1,y1,xs);
y2f = interp1(x2,y2,xs);
d = y2f - y1f

d = 1×7

1.2000 1.0333 0.2000 0.4000 0.1333 -0.2000 0

max(d)

ans = 1.2000

% plot the two curves and show the distances 
plot(x1,y1,'ro-',x2,y2,'bo-'); hold on
for l = 1:numel(xs)
	plot([1 1]*xs(l),[y1f(l) y2f(l)],'m:')
end

[Fangjun Jiang]

Good point. Y data could be at different X points.

[shagun chaudhary]

Thank you so much it works, but I could i find the corresponding X value to maximum y difference. It would be great if you can help me in this .

ThANK YOU SO MUCH

[shagun chaudhary]

Thank you so much it works, but how could i find the corresponding X value to maximum y difference. It would be great if you can help me in this .

ThANK YOU SO MUCH

[DGM]

[~,idx] = max(d); % get location of max d
maxd = d(idx)
maxx = xs(idx)

[shagun chaudhary]

Thank you so much sir. It been great help!