The rapid development of the world economy in recent
years has been accompanied by increasing global movement
of goods and materials.^^^^^ The vessels responsible for mass
transportation of these goods are increasing in both size and
number.^^^^ Consequently, vessel congestion and accidents in
main ocean transport routes are now frequent.^^^^^ As the number
of vessels increases, the risk of marine accidents becomes
ever higher.^^^^ Most of these maritime accidents occur in
narrow channels and coastal waters where the ships are
crowded [1].^^^^ Most ship operators lack the advanced
navigation technology and extensive navigation experience to
negotiate such risky ocean areas.^^^^ This situation is especially
dangerous for ship operators with immature navigation
experience because the danger is compounded by stress.^^^^
Therefore, the provision of navigational information has
become timely and important.^^^^^ Over the past years, several
studies have focused on the presentation of navigational
information. However, little attention has been devoted to the
actual navigational situation of vessels, which is essential for
understanding water bodies and ensuring maritime safety.