Abstract
A method includes steps of: receiving map data that contains a map of a working area, the map of the working area being at least defined within a closed outer boundary; generating a Voronoi diagram based on the outer boundary, the Voronoi diagram including at least one Voronoi cell having an edge that is composed of a plurality of Voronoi points; selecting at least one of the Voronoi points as a target point; and capturing, at a target location in the working area that corresponds to the target point in the Voronoi diagram, an image of the working area to serve as the visual record.