Improving the Study of Soil and Landscapes GIS visualization clarifies relationships between soils, topography, and land use By Barbara Shields, Esri Writer Understanding how soils occur and how they vary across landscapes is a critical skill for today's agronomists. At Purdue University (Indiana), it is an integral component of the curricula. Darrell G. Schulze, professor of soil science, and Phillip R. Owens, assistant professor of soil geomorphology and pedology, coteach the class Soil Classification Genesis and Survey. They incorporate the latest version of ArcGIS to study the relationships between soils, topography, land use, and geology. Using GIS in the classroom and in the field helps students better understand soils and the landscapes in which they occur and recognize geological features that indicate different soil types. At the beginning of the class, most students know little about geography and GIS, but by the time they complete the course, they are able to access geographic data and view it with GIS tools. The teachers use GIS to share data with the students who, in turn, use it to observe different points in the landscape. Schulze accesses the U.S. Department of Agriculture (USDA) soil survey data as well as data from the Indiana Spatial Data Portal and the Indiana Geological Survey. "This data is robust," notes Schulze. "In 2007, the USDA completed digitization of soil data for Indiana, "GIS is helping us to teach concepts in our class that would otherwise take students years of field experience to acquire." —Darrell G. Schulze, professor of soil science at Purdue University so I can access soil data for any county in the state." Schulze downloads this data along with high-quality aerial photography and highresolution digital elevation model (DEM) data. Using GIS, he aggregates the data into files that fit class objectives. For example, he created a dominant soil Purdue students take GIS on the road to better understand the real world of soil assessment via digital data. 62 ArcUser Summer 2009 parent material model that groups polygons so that students can see relationships that are not readily apparent from traditional representations of soil survey data. With GIS, students are able to visualize the geomorphology of their study area. Owens stated "Students easily relate to the features they can see while they are standing in a field; however, larger landscape features that occur over kilometers are much more difficult to immediately understand. Teaching soil geomorphology using Tablet PCs and GIS provides the students with tools to see relationships over large distances and has revolutionized our ability to teach spatial relationships." Students can see, for instance, that Purdue is located in a part of the world that was glaciated 20,000 years ago and understand close correlations between the soil parent material and the surficial geology. The DEMs highlight relevant topographic variations. By comparing this with soil data, students make www.esri.com