1. FIGURE 4.1. On the CDC website, the choice of “natural” colors for the background image and the use of red–yellow–green sequence of colors to indicate threats follows established graphic conventions in most of the world for indicating danger levels.
From A Primer of GIS, 2nd edition, by Francis Harvey. Copyright by The Guilford Press.

2. FIGURE 4.2. A simple map that follows common conventions for showing areas forms the background for preparing more complex analytical overviews using this map-based tool for analyzing markets for small businesses in the United States.
From A Primer of GIS, 2nd edition, by Francis Harvey. Copyright by The Guilford Press.