diff --git a/gisea/utils.py b/gisea/utils.py
index dbf90f4..9ae378e 100644
--- a/gisea/utils.py
+++ b/gisea/utils.py
@@ -3,7 +3,7 @@
 import json
 from time import time
 import igraph as ig
-
+import gzip
 
 def read_data(jsonfilename):
     t0 = time()