An Atlas Diagram is a type of MAP that shows the physical features of an area. It is often used to illustrate the topography of a region, such as mountains, rivers, and other geographical features. The term 'Atlas Diagram' is derived from the Greek Titan Atlas, who was said to have held up the heavens. The term 'MAP' is a three letter acronym for 'Modified American Plan, ' which is a type of MAP that is used to show the boundaries of states, counties, and cities.