diff --git a/swash/processing/post.py b/swash/processing/post.py
index 2dbbf82..34e6318 100644
--- a/swash/processing/post.py
+++ b/swash/processing/post.py
@@ -70,7 +70,7 @@ fig.tight_layout()
 
 fig_r, ax_r = plt.subplots()
 
-ax_r.plot(1/phi_eta[0], R)
+ax_r.plot(1 / phi_eta[0, 1:], R[1:])
 ax_r.autoscale(axis="x", tight=True)
 ax_r.set(ylim=(0, 1), xlabel="t (s)", ylabel="R")
 ax_r.grid()