The Map consists of 2 sets of lines – horizontal and vertical. In simple terms, the horizontal lines represent the Latitude while the vertical lines represent the Longitude.
Latitude lines move from North (top) to South (bottom). A Latitude of 0° refers to the middle horizontal line, or what can be called the x axis.
On the other hand, Longitude lines move from East (right) to West (left). A Longitude of 0° refers to the middle vertical line, or what can be called the y axis.