diff --git a/SimPEG/Maps.py b/SimPEG/Maps.py
index 15504094..9cd067b3 100644
--- a/SimPEG/Maps.py
+++ b/SimPEG/Maps.py
@@ -3,6 +3,7 @@ from scipy.sparse.linalg import LinearOperator
 from Tests import checkDerivative
 from PropMaps import PropMap, Property
 from numpy.polynomial import polynomial
+from scipy.interpolate import UnivariateSpline
 
 class IdentityMap(object):
     """