diff --git a/heatmap/heatmap.py b/heatmap/heatmap.py
index 721ffa5..173e5cc 100644
--- a/heatmap/heatmap.py
+++ b/heatmap/heatmap.py
@@ -117,7 +117,7 @@ def heatmap(self, points, dotsize=150, opacity=128, size=(1024, 1024), scheme="c
             arrScheme, arrFinalImage, opacity, self.override,
             ctypes.c_float(self.area[0][0]), ctypes.c_float(
                 self.area[0][1]),
-            ctypes.c_float(self.area[1][0]), ctypes.c_float(self.area[1][0]))
+            ctypes.c_float(self.area[1][0]), ctypes.c_float(self.area[1][1]))
 
         if not ret:
             raise Exception("Unexpected error during processing.")