Autonomous search for objects in known map

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I have a map of the area, and so far I've given the robot manually around 10 points that are 2D Nav Goals, but I would like to tell the robot to autonomously search the space. Is there any way to do that? For example is it possible to tell it to walk around the perimeter of the map, let's say being half a metre away from the wall at all times? I would prefer something other than random walks, because that is too, well random, and it might take a long time to go around the whole map. Since I already know the layout, I would like to somehow use that information to systematically visit every place.