The advantage of displaying radar overlay on an ECDIS is that it allows for what?

• A. It allows for true position correlation
• B. It provides faster target plotting on the radar screen
• C. It reduces the need for chart data
• D. It makes radar data harder to interpret

Answer: (A)

Overlaying radar on an ECDIS provides true position correlation by tying radar echoes to chart coordinates. When the radar image is projected onto the electronic chart, you can see exactly where each radar target sits in relation to charted features like coastlines, buoys, and other vessels. This geographic alignment lets you confirm identities and tracks by matching radar returns to known chart positions, reducing ambiguity and enhancing situational awareness for safe navigation. For this to work reliably, the system relies on accurate inputs from navigation sensors (heading, gyro, GPS) so the radar image is aligned correctly with the chart. The overlay doesn't replace chart data, nor does it automatically speed up target plotting or make radar harder to interpret; its main benefit is providing a geographic reference that enables true position correlation.