NewPoint returns a new Point populated by the passed in latitude (lat) and longitude (lng) values.

NewPolygon: Creates and returns a new pointer to a Polygon composed of the passed in points.

According to Wikipedia, the Earth's radius is about 6,371km.

Represents a Physical Point in geographic notation [lat, lng].

A Polygon is carved out of a 2D plane by a set of (possibly disjoint) contours.