Cartesian Coordinate Systems - 3D Math Primer for Graphics and Game Development - page 6

Figure 1.4. Map of the hypothetical city of Cartesia

1.2.1 An Example: The Hypothetical City of Cartesia

Let's imagine a fictional city named Cartesia. When the Cartesia city
planners were laying out the streets, they were very particular, as illustrated
in the map of Cartesia in Figure 1.4.
As you can see from the map, Center Street runs east-west through the
middle of town. All other east-west streets (parallel to Center Street) are
named based on whether they are north or south of Center Street, and how
far they are from Center Street. Examples of streets that run east-west are
North 3rd Street and South 15th Street.
The other streets in Cartesia run north-south. Division Street runs
north-south through the middle of town. All other north-south streets
(parallel to Division Street) are named based on whether they are east or