diff --git a/galsec.py b/galsec.py
index f236c6d..ed54234 100644
--- a/galsec.py
+++ b/galsec.py
@@ -335,9 +335,9 @@ class Galsec:
             x_bin = np.trunc(self.data[fluid]["position"][:, 0] / delta_x)
             y_bin = np.trunc(self.data[fluid]["position"][:, 1] / delta_y)
             z_bin = np.trunc(self.data[fluid]["position"][:, 2] / delta_z)
-            self.data[fluid]["x_bin"] = x_bin
-            self.data[fluid]["y_bin"] = y_bin
-            self.data[fluid]["z_bin"] = z_bin
+            self.data[fluid]["x_bin"] = (x_bin + 0.5) * delta_x  # Store the middle value
+            self.data[fluid]["y_bin"] = (y_bin + 0.5) * delta_y  # Store the middle value
+            self.data[fluid]["z_bin"] = (z_bin + 0.5) * delta_z  # Store the middle value
 
     def sector_analysis(
         self,