Topographic Maps
A Topographic-Map is a detailed and accurate graphic representation of cultural and natural features on the ground. The distinguishing characteristic of a topographic map is the use of Contour-Lines to show the shape and Elevation of the Terrain. These lines connect points of equal height above Sea-Level, effectively depicting the Relief of the Earth surface in two dimensions.
The United-States-Geological-Survey (USGS) is the primary agency responsible for topographic mapping in the United-States. Modern maps are created using advanced techniques such as Photogrammetry and Lidar. According to the USGS Official Site, these maps are vital for Engineering, Resource-Management, and Environmental-Science. Additional educational resources are provided by National Geographic.
Essential components include the Map-Scale, which relates distances on the map to actual distances on the ground, and the Map-Legend, which identifies symbols for features like water bodies, vegetation, and man-made structures. Today, Geographic-Information-Systems (GIS) allow for the creation of digital Digital-Elevation-Models based on topographic data.