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MATLAB Creating a Surface Plot Alan Harris Liz Kuhn Amanda Williams Jessica Warrington What is a Surface Plot? A surface plot is a graph of a threedimensional function – Any function of the type z=f(x,y) Today, we will create a simple hyperbolic paraboloid of form z=x^2-y^2 What Should This Look Like? Starting MATLAB Double Click on the MATLAB Icon Wait until the Command Window loads Creating the Domain This is the area in Cartesian space over which the function will be graphed Enter the following commands in the Command Window: – x = linspace(-5,5,51); – y = linspace(-5,5,51); The domain is x[-5,5];y[-5,5] The domain is divided into 51 equidistant points Creating the Mesh The last two commands made a 51 element x array and a 51 element y array Now, we are creating two 51 by 51 matrices, one for x, one for y 1 2 3 – If x was [1,2,3], this makes 1 2 3 1 2 3 Enter into the Command Window: – [X,Y] = meshgrid(x,y); Using the Mesh Now, use the X and Y matrices to create the function Enter into the Command Window: – Z = X.^2-Y.^2 ; The “.^” means to square each individual element The “-” follows normal matrix subtraction This creates a 51 by 51 matrix of z values Plotting the Function This is where MATLAB does all the work for you Enter into the Command Window: – surf(X,Y,Z) This creates a new window in which your function is graphed Adding Labels No graph is complete without labels – The title command is “title(‘Title Name’) – To label the x-axis, the command is “xlabel(‘The Label’) The same is true for the y- and z-axes Conclusions With a few simple commands, MATLAB can perform complex operations and create useful images