Heliographic projection to compare in situ B_R field sign reversals to the hammerhead occurrence rate. Positive in situ B_R is marked in red and negative in situ B_R is marked in blue. The PSP trajectory (backmapped to 2.5R_⊙) is colored by B_R, where the perihelion is marked by higher opacity and larger markers. The fainter colored parts of the trajectory fall outside the dates we consider for the encounter, where we do not use hampy to detect hammerheads. We plot the fractional occurrence rate of the hammerheads as lime green circles in 1° bins in heliographic latitude–longitude. The sizes of these circles are proportional to the fraction of VDFs that get flagged as hammerheads in the specific latitude–longitude bin. The solid black line marks the HCS at 2.5R_⊙ using PFSS. The top panel shows E04, while the bottom panel shows E22. The orange (blue) shaded regions indicate coronal holes formed by radially outgoing (incoming) open magnetic field lines.