The presentation of hydrographic and traffic information on one screen is one of the great advantages when navigating with ECDIS. Briefly the advantages are:

• All data for navigating in difficult situations is available at any time,
• The GPS/DGPS position can be checked by radar image,
• Differences of reference systems and sensor data can be detected,
• Radar echoes can be better identified,
• Anomalies with floating aids to navigation (e.g. buoys in strong currents or adrift) can be easily detected,
• Radar specific limitations can be compensated for to some degree,
• Transfer of Radar bearings and distances on a sea chart becomes superfluous and human error can be limited.

Overlaying hydrographic data with Radar/ARPA information can produce problems. These are:

• Sea clutter,
• Information overflow,
• Mutual coverage of information,
• Priority of presented data,
• System failure e.g. "black out" will affect two navigation systems,
• If ARPA only targets displayed then all other Radar targets will be suppressed.

The ECDIS performance standard requires that Radar/ARPA data does not affect the ECDIS presentation.