Spherical coordinates
From Conservapedia
Spherical coordinates are a way to describe the location of a point in three-dimensional space based on 
, the distance from the origin (where 
); 
, the angle between the point and the x-z plane (in the positive x direction); and 
, the angle between the point and the z axis (in the positive z direction). Thus, each point is described by: 
.
In a sense, spherical coordinates are coordinates on a sphere just like polar coordinates are coordinates on a circle.
The equations converting the parameters are as follows:
The Jacobian in spherical polar coordinates is 
so that 
.
