diff --git a/src/tools.py b/src/tools.py
index 1d3590d6de48c407de35087cd2eadd024f9c97e6..2e79b3e52f0a26f92f9ef9bd627aacb4526656aa 100644
--- a/src/tools.py
+++ b/src/tools.py
@@ -186,4 +186,4 @@ def wkt_to_authority(wkt):
     elif srs.GetAuthorityCode('GEOGCS') != None :
         return srs.GetAuthorityName('GEOGCS'), srs.GetAuthorityCode('GEOGCS')
     else:
-        raise KeyError("Unable to get authority from %s" % wkt)
+        return "Unknown", "Unknown"