A topographic map presents the shapes of geologic features such as mountains, valleys, and plains using a series of contour lines to indicate areas of equal elevation. Prior to the release of topoBuilder, U.S. Geological Survey (USGS) topographic maps were available through the USGS Store or from outdoor recreation-focused retailers such as REI or Cabelas.

The USGS topoBuilder web application allows users to generate a customized, on-demand map of most areas within the bounds of the U.S. and its Territories. These high-resolution maps are suitable for printing or can be accessed using a geo-enabled mobile app such Avenza Maps or Gaia GPS. In this task sheet you will learn how to use the topoBuilder application to generate a customized map of the Des Moines River near a popular state park in central Iowa.