Removing complex numbers from a set of data

I am trying to plot a set of data as a surf plot. The y and x data are fine. However, the z data comes in the form of a complex number. I am trying to zero all of the complex parts so that i can plot it.

y = ydata;
x = xdata;
z = dat.smx; %getting the data from a structure array
z =complex(real(z),0.);
surf(x,y,z)

This acheives what i want and gives me my 192x4096 of only real numbers but the variable is still saved as a complex double so matlab still does not let me plot it.

z(imag(z) ~= 0) = 0;

I tried another way with the above line, which does also remove the imaginary part and does make it a normal double which can be plotted. But it also ends up completely zeroing all but two rows of my data.

763996.405269850 + 0.00000000000000i	-6378786.63933523 + 0.00000000000000i	
830122.423191093 - 394079.620750282i	-5091297.01649812 + 2603687.55800279i	
967512.178415854 - 1059879.31296563i	-2457122.99646261 + 3059394.68904817i	
752434.554058071 - 2280059.15542211i	-896237.599749785 + 1334068.00008166i	
-658985.067753466 - 3695451.52098837i	-1627383.69202439 - 594734.648456007i	

My data looks like a larger version of above

Any help is appreciated

Answer 1

[Dave B]

If you want to make a surf of the real component of z:

surf(x,y,real(z))

If you want to make a surf of the complex magnitude of z:

surf(x,y,abs(z))

Quick example of getting real component/magnitude of a complex number:

a=[1+1i 1-1i 3+3i]

a = 
   1.0000 + 1.0000i   1.0000 - 1.0000i   3.0000 + 3.0000i

real(a)

ans = 1×3

1 1 3

abs(a)

ans = 1×3

1.4142 1.4142 4.2426