It is a Great Circle . Great circles are circles drawn on a sphere with the same radius as the sphere. The Equator is the zero for Latitude . Lines of Latitude can be run north and south of the Equator. These are a series of Small Circles and are shown on the left sphere below.
Small circles are circles drawn on a sphere that are smaller than the sphere.
Zero Latitude is the Equator. All lines of Latitude are parallel to each other. For reasons that we will discuss later, there are four other special lines of Latitude on the Earth. These are given names and are listed below. These four lines of Latitude divide the Earth into climatic zones.