Mobile GIS in Geologic Mapping Exercises

Article excerpt

ABSTRACT

We have been developing and teaching the components of mobile GIS in Field Methods courses and will be incorporating them into Structural Geology exercises. Since the bedrock in east central Indiana is topographically invariant, non-inclined, and often not exposed, we have developed a new introductory GIS project that simulates structural features. It utilizes inclined, one-foot square planes that are placed upon a series of pedestals stationed in an open area, each accompanied by a petrographic hand sample and an age label. An introductory one-hour session is held in the field to teach acquiring GIS data. Then the students independently acquire geologic data such as GPS-located "outcrop" locations, rock descriptions, and strike/dip, and enter the geologic data on a base map using Mobile GIS software (ArcPad). In a two-hour follow-up class students learn to add their field data to a map in the PC-based GIS program ArcMap. Strike/dip symbols are computer-generated and displayed at the GPS coordinates taken in the field. This exercise supports spatial organization with data availability of Mobile GIS in the field and prepares students for GIS-based mapping projects in our Field Camp in Wyoming.

INTRODUCTION

Mobile GIS, that is recording field data digitally and connecting them in-situ with geographical points on a map using GPS and GIS, is an emerging technology and can be used as a tool in geologic field mapping and data collection. Over the last years, the Ball State University Geology Department has integrated this technology in many of its geology courses, from field methods to structural geology to our five-week summer field camp. Being an outdoor method, clearly a lab is required to teach students the skills. Traditionally, we have introduced GPS and mobile GIS to students in our field methods class. However, due to a curriculum restructuring, these exercises are incorporated into other classes. The GPS-based exercises are run in structural geology where field mapping is now being emphasized. There are several advantages to this approach: students taking the upper-level structure class already have experience in map reading and skills in rock description. In the structure class, they learn to recognize structural features in the field and on maps. So, at least theoretically, exercises introducing GIS methods at this level can focus on applying the new technique while integrating advanced geological tasks. Structural geology is also a class that is required for field camp, where this technique is widely used, as described later.

The choice of location for this introductory lab proved to be not easy for us, given the topography and geology encountered in central Indiana - flat lying carbonates covered by till. We take students on field trips to Kentucky and, like most other Midwestern universities, to the Appalachians (Malone, 1999), but we like the students to know how to apply GIS methods beforehand in order to utilize time on these trips more efficiently. As a compromise, we developed this campus-based exercise. On-campus exercises are popular because they are easy to organize, do not require additional funding and travel time such as van-based field trips, and avoid increasing liability issues encountered with using vans (Keown, 1984). Other schools successfully use the geology encountered in and on campus buildings to conduct campus walking tours (Weiss and Walters, 2004), or have built rock gardens to make geology available (Dillon et al., 2000) For our exercise, we want to be able to control the settings, which makes using buildings on campus impractical, and to create a rock garden goes beyond the scope of our exercise. Accordingly, we developed temporary devices that mimic petrographic and structural features, that are easily movable, cheap, and that do not require as much preparation and administrative work as, say, creating a rock garden.

Our goal is to introduce the students to the new mobile GIS technique while incorporating geologic tasks they already know, such as strike/dip measurements and rock descriptions. …