The integration of AIS with 'Electronic chart display and information system' (ECDIS) has resulted in a revolution in the field of offshore marine communication. ECDIS, better known as 'Electronic nautical chart', is a name given to nautical chart representations on computers (Scheuermann, Wolf, 1996). However nautical chart representation is one of the aspects of ECDIS. ECDIS is a complete information system, providing all necessary information about whatever is displayed on the chart (Scheuermann, Wolf, 1996).
Targets from the radar and from AIS can simultaneously be plotted on an electronic chart (Strenge, Rainer, & Bober, Stefan, 2004). Thus signals from both radar and AIS can be acquired and depending on the requirement, the information can be collected from either of the two sources or from both of them. The positioning of the target on the electronic chart is carried out by DGPS positioning system and in addition through radar map matching process that was developed by Stuttgart University (Strenge, Rainer, & Bober, Stefan, 2004). The ships have large electronic chart displays (ECDIS) installed on them on which AIS data and radar information from other ships is superimposed. These large displays have nowadays been replaced by small and portable computers.
The port services have the responsibility to monitor the ship traffic.