I will post an image which believe it is essential to understand the question: See the image: Figure book
Spherical coordinates $r, \theta, \phi$ are perfectly intuitive because the angles $\theta$ and $\phi$ correspond, respectively, to longitude and latitude on the surface of the Earth, and $r$ is the distance to the center of the Earth.
I believe the notation is wrong, since theta is the angle wrt north and south axis, shouldn't be the reverse?
On
The $(r,\theta,\phi)$ convention for three dimensional spherical polar coordinates is used in mathematics, as it follows naturally from the $(r,\theta)$ convention used for the two dimensional case. However, physicists for some bizarre reason prefer $(r,\phi,\theta)$. What makes it even more confusing is that the very order the coordinates are written is also sometimes switched. Some authors order it as radial, azimuthal, polar which seems reasonable whereas some authors use radial, polar, azimuthal instead. So even if the author says "I'll use the $(r,\phi,\theta)$ convention" it might not even mean what you think it does!
So, if you're using spherical coordinates, it's best to explicitly state the coordinate transformation you're using. Here's a passage from some recent work of mine:
I will also use the $\displaystyle ( r,\theta ,\phi )$ convention for spherical coordinates, as used by Wolfram Mathworld. Explicitly, the coordinate transformation is \begin{equation*} \begin{bmatrix} x\\ y\\ z \end{bmatrix} =\begin{bmatrix} r\cos \theta \sin \phi \\ r\sin \theta \sin \phi \\ r\cos \phi \end{bmatrix} \end{equation*}
Suggested reading: https://mathworld.wolfram.com/SphericalCoordinates.html
Which textbook is this taken from? If it is a mathematics textbook, the convention is that $\phi$ corresponds to latitude and $\theta$ to longitude, but if it is a physics textbook, then $\theta$ will usually correspond to latitude and $\phi$ to longitude. This sort of confusion is why I usually stay away from spherical coordinates.