When I tried to open my world with gazebo, gazebo src/coverage/coverage/worlds/willow-pr2-5cm.world it said :

Error [parser_urdf.cc:2722] Unable to load file[/home/lempereur/catkin_ws/src/coverage/coverage/worlds/willow-pr2-5cm.world].
Error [parser.cc:278] parse as old deprecated model file failed

I can't understand what is my mistake