diff --git a/nielsen_volumes.py b/nielsen_volumes.py
index 858ac58..5f918e1 100644
--- a/nielsen_volumes.py
+++ b/nielsen_volumes.py
@@ -132,7 +132,9 @@ def findZerochainage(chainage0, elevation0, max_beach_slope=5, min_beach_slope=5
     else:
         #find the slope between the last two points
         try:
+            np.seterr(all='ignore')
             beachslope = 1/((elevation0[-2] - elevation0[-1])/(chainage0[-1] - chainage0[-2]))
+            np.seterr(all=None)
         except ZeroDivisionError:
             beachslope= 999
         if beachslope>min_beach_slope: