You extract the contours wrong, at least if you have multiple contours at the same level v(i). It is simpler if you plot all the contours at once:
[K,c] = contour(idq,isd,Psi_abs,v);
Then you have to extract them segment-by-segment. The format for K is:
K = [level1, x1_1,x1_2,.. ,x1_n1,level2, x2_1,x2_2,..,x2_n2,level3
n1,y1_1,y1_2,..,y1_n1, n2, y2_1,y2_2,..,y2_n2, n3]
So you'll have to extract your contour-segments something like this:
iC = 1;
idxC = 1;
while iC < size(K,2)
nP = K(2,iC); % number of points in current contour
xC{idxC} = K(1,iC+(1:nP)); % x coordinates of current contour
yC{idxC} = K(2,iC+(1:nP)); % y coordinates of current contour
iC = iC+nP+1; % Start-point of next contour
idxC = idxC + 1; % next contourline index
% plot(xC{idxC-1},yC{idxC-1},'b.-') %% If you want to look at the separate
% pause %% segments as they are separated.
end
That would give you a pair of cell-arrays with the x and y coordinates for the contour-segments, that you then can reinterploate and doodle with as you see fit, perhaps the Interparc contribution is of interest to you...
HTH
