A Cartesian graph is really just two number lines that cross at 0. These number lines are called the horizontal axis (also called the x-axis) and the vertical axis (also called the y-axis). The place where these two axes (plural of axis) cross is called the origin.
Cartesian graph can be used to pinpoint where you are on a map or graph.
A point (x,y) shows the distance y in feet a person walks in x hours where x-axis represents time in hours and y-axis the distance in feet.