It's difficult to take an image of essentially a
radar snapshot and make much out of it. Much depends on the topography of the island, the state of the tide, and weather conditions.
This might be another example of a reason to not overlay
radar returns over a
chartplotter display as well. It creates a needless confusion. It's also interesting that most people, if the
radar picture is less than perfect are reluctant to rely on it-which is probably wise-but will willingly rely on the
GPS picture due to it's precise clarity. Just the opposite should be the case.