Why are maps very important? How do you make a map? Objective Students will be able to use written directions to create a map giving: • Cardinal directions • Landmarks and distances Background When the Corps of Discovery began its journey across the western reaches of the North American continent, little was known about much of the route. They did know the Missouri River extended far beyond the Mandan villages in present day North Dakota. Information learned in conversations with fur traders and American Indians of the region hinted at the geography of the land, but these details had not been Duration: 60 Minutes.