diff --git a/ogr2osm/ogr_datasource.py b/ogr2osm/ogr_datasource.py
index 1fcb0b9..729e3ef 100644
--- a/ogr2osm/ogr_datasource.py
+++ b/ogr2osm/ogr_datasource.py
@@ -98,6 +98,9 @@ def set_query(self, query):
 
 
     def __get_source_reprojection_func(self, layer):
+        if layer is None:
+            return None
+        
         layer_spatial_ref = layer.GetSpatialRef()
 
         spatial_ref = None