Geo::Google::Segment is an annotated segment of a path.
# you shouldn't need to construct these yourself,
# have a Geo::Google object do it for you.
Google Maps is able to serve up directions between two points. Directions consist of two types of components:
1. a series of points along a "polyline".
2. a series of annotations, each of which applies to a contiguous
range of points.
In the Geo::Google object model, directions are available by calling path() on a Geo::Google instance. The return value is a Geo::Google::Path object, which is a composite of Geo::Google::Segment objects, which are in turn composites of Geo::Google::Location objects.