Google maps are based on a Mercator projection of the world, it projects the world (a sphere) on a two-dimensional plane. The big advantage of a Mercator projection is that it creates a square, which is easily handled by a computer system as it allows access through Cartesian axes. The poles, however, are skewed (enlarged).
Prerequisites for geographical mapping:
a location or region. W.r.t. Google maps there are three ways of getting a location:
clicking on a map to add a pointer, message, or line
using x-y latitude-longitude system
specify a name (e.g. country or address)
optional: value related to location or region (e.g. temperature)