iOS 6 famously included Apple’s home-grown Maps, and to be frank, they aren’t always awesome. While Google’s offering isn’t perfect, either, it will be nice to have both when out and about.
Correction: “aren’t always awesome” should be replaced by “are utter shit”.
MarineTraffic.com has a Google Maps mashup that shows vessel traffic and positions. Their FAQ describes how position data is collected:
The system is based on AIS (Automatic Identification System). As from December 2004, the International Maritime Organization (IMO) requires all vessels over 299GT to carry an AIS transponder on board, which transmits their position, speed and course, among some other static information, such as vessel’s name, dimensions and voyage details.