Hi Priya. It might be helpful to understand how you would like to define the direction, and does the magnitude matter? What are the values you are looking to use for the quiver plot?
If you answer those questions, I am sure someone would be able to help you answer the question more effectively.
As a quick solution, I would advise doing something as follows:
hold on;
quiver3(x,y,z1,u,v,w);
Hold will allow you to add the quivers to the plot, and the u,v, and w are the directional cosine values that I am referring to would be useful to know what they are in your above file.
Hope that makes sense, and helps you,
Michael
