What does a Plan Position Indicator (PPI) display?

• A. A circular radar display showing range and bearing to all targets relative to the radar site
• B. A computer-generated text log of weather observations
• C. A rectangular map with aircraft positions and labels
• D. A vertical profile of wind speed and direction

Answer: (B)

A Plan Position Indicator shows a circular radar image centered on the radar site, displaying weather echoes by range from the center and bearing around the circle. This lets you see where precipitation is located and how it’s arranged around the radar, in a true plan-view (two-dimensional) layout. The display is created by the radar’s rotating beam (or equivalent scanning pattern), mapping echoes to azimuth (direction) and range (distance). This is fundamentally different from a text log of observations, which would be written data; from a rectangular map with aircraft positions, which is a different style of display; and from a vertical wind profile, which shows wind speed and direction with height rather than around the radar in plan view.