I am plotting a 3D graph and a contour of the same. Then I plot few lines on the contour plot. I want to know the value of the contour where the line crosses the contour and also the coordinates where intersection happens. Can anyone please help me with this
I assume by 3D graph with contour, you mean you have 3D data represented in 2D by a contour plot? Or do you mean something like contour3 or isosurface?
Assuming the former, the coordinates of the contour lines generated via
[c,h] = contour(x,y,z);
are found in the c matrix. There are a few File Exchange functions (like contourcs) that can simplify the task of extracting those coordinates.
If you have the Mapping Toolbox, polyxpoly can calculate the line intersections. Otherwise, there are a bunch of FEX entries to calculate the intersections of two lines/curves (like this one).