Answer
Please see the figure attached.
Work Step by Step
In spherical coordinates, $\theta$ is the polar angle of the projection $Q$ of a point $P$ onto the $xy$-plane. Since it is constant $\theta = \frac{\pi }{2}$, it is located in the $yz$-plane. While $\phi$ is the angle of declination, which measures how much the ray through a point $P$ declines from the vertical. Since it is constant $\phi = \frac{\pi }{4}$, this is a line in the $yz$-plane. Since $\rho \ge 1$, the line starts from $\rho=1$.
