Objects (points, lines, polygons) can be enhanced to highlight specific variations on a theme through the creation of a Thematic map. The basic data is overlaid with graphic styles (e.g. colour shades, hatch patterns) to display information on a more sophisticated level. For example, population density between urban and rural areas may show the cities in deep red (to indicate a high ratio of inhabitants per square mile), while showing remote areas in very pale red (to indicate a low concentration of inhabitants).