Need to define map_name, no default value

launch/nav.launch

@@ -19,7 +19,7 @@
   <arg name="use_map"                    default="true"/>
   <arg name="use_map_server"             default="true"/>
     <arg name="map_path"                 default="$(find iri_rosnav)/maps"/>
-    <arg name="map_name"                 default="willow"/>
+    <arg name="map_name"                 />
   <arg name="use_amcl"                   default="true"/>
     <arg name="amcl_config"              default="$(arg path)/amcl.yaml"/>
     <arg name="initial_x"                default="0.0"/>