What does the top of the PPI sweep represent?

The top of the PPI (Plan Position Indicator) sweep represents true north or the ship's heading. This means that the information displayed on the PPI is oriented with true north at the top of the screen, allowing navigators to easily interpret the orientation of other displayed elements in relation to their current course. This consistent reference point is crucial for accurate navigation and situational awareness, as it helps navigators understand how other vessels, landmarks, or navigational aids are positioned relative to their own heading.

An understanding of true north is fundamental for effective maritime navigation, as it aligns with compass readings and chart orientation, ensuring that navigators can make informed decisions based on reliable directional information.