Get values of the particular line from surf plot

I'm intersted to get all the values of the line 2- curve - marked in figure

load('jj.mat');
A1  = jj;
figure
A1(A1>0.05) = NaN;
surf(A1);shading interp;view(2);

figure
contour(A1); shading interp; view(2)

figure
v = [0.045 0.055];
contour3(A1,v); shading interp; view(2)

How Shall I get only this lower curve in a separate figure and then get all the Y values ?

Answer 1

[Konrad]

Hi Ramesh,

the contour3() function returns the contour matrix (see help) containing x- and y-coordinates of the contour. You can use these to extract the desired part of the contour:

figure
v = [0.045 0.055];
contMat = contour3(A1,v); shading interp; view(2)

idx = contMat(1,:)>60 & contMat(2,:) < 850;

contSubset = contMat(:,idx);

Now contSubset contains x coordinates of the marked part in the first row and y coordinates in the second row.

Best, Konrad

[Ramesh Bala]

Hi Konrad,

Thank you for your valuable reply.

Sorry for the question again : I would like to see only the circle region ( as in pic) second part of contour3 plot.

When I tried to plot subsets it shows different figure and not matching what shows in contour3 plot ?

Thanks again.

plot(contSubset(1,:))

plot(contSubset(end,:))

[Konrad]

Try

figure;
plot(contSubset(1,:),contSubset(2,:),'.'); % 1st row of contSubset is used as x-coordinates and 2nd row as y-ccordinates
set(gca,'Xlim',[1 234],'YLim',[1 2643])

this should look like the region marked in your figure.

[Ramesh Bala]

Thank you so much Konrad .The lines made was so user friendly and quick.