diff --git a/modules/img/base/pymod/export_xtal_map.cc b/modules/img/base/pymod/export_xtal_map.cc
index 77a58267b50f0341564c16ee3bcfaf53c0de2821..55f2ff8264df5bceeaeb24f749ef77e504958c2a 100644
--- a/modules/img/base/pymod/export_xtal_map.cc
+++ b/modules/img/base/pymod/export_xtal_map.cc
@@ -19,6 +19,8 @@ void export_XtalMap()
          return_value_policy<copy_const_reference>())
     .add_property("unit_cell", make_function(&XtalMap::GetUnitCell, 
                   return_value_policy<copy_const_reference>()))
+    .add_property("unit_cell_size", make_function(&XtalMap::GetUnitCellSize, 
+                  return_value_policy<copy_const_reference>()))
   ;
 
 }
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