Barbara M. Linde 
All About Topographic Maps [PDF ebook] 

Which trail has a gentle slope? Where are the highest mountains along the Appalachian Trail? Is there a lake along the route? As students read this engaging volume, they will learn how to use United States Geological Survey (USGS) contour maps to answer these questions. They’ll get an historical overview of how surveyors used to create these maps, and how technology now helps create more accurate maps. Students will construct 3D models of areas on a topographic map.