A polar histogram showing the angle between an incoming pass and the subsequent outgoing action (pass or carry) by the receiver. Unlike standard passing sonars (which show absolute pass direction), relative sonars show what the player does RELATIVE to where the ball came from. 180° = the player maintained the ball's direction (turned and progressed); 0°/360° = the player sent the ball back to where it came from. Color intensity represents frequency; bar length represents median distance. This concisely captures a player's turning behavior — do they turn and drive forward, or receive and recycle?
(1) Identify passing sequences: pass → ball receipt → subsequent action (pass or carry). (2) Compute the angle between the incoming pass vector and the outgoing action vector. Use the unsigned angle between the two lines (0° to 180°), where 180° = ball continues in the same direction, 0° = ball returns to origin. (3) Build polar histograms binned by angle. Encode frequency (color) and median length (bar length). (4) Optionally filter by: receiving zone (back passes only, using an angular cone definition), pressure state (under pressure vs. not), pitch zone.
Key distinction from standard sonars: Rakitić receives short passes from the left and sends long diagonal balls to the right — his standard sonar shows rightward long passes. His relative sonar shows 180° (he maintains the direction of the ball) with long median distances. The relative sonar captures the BEHAVIOR, not just the direction.