MOBILE GIS IN GEOLOGIC MAPPING EXERCISES

The validation of geologic data in the field and the display of geologic knowledge using the emerging technology of Mobile GIS enhance the accuracy of geologic map exercises. In this method, a hand-held computer (PDA) displays GPS-located geologic data on a base map using Mobile GIS software (ArcPad). Strike/dip symbols are computer generated and displayed at the GPS coordinates taken at outcrops. Recorded dip directions and anticipated linear geologic features can be confirmed in the field by comparing geomorphology with the spatial distribution displayed on the PDA. Locations of identified rock formations and similarities in lithologies can be queried and displayed to assist in the derivation of formation contacts.

The Geology Department at Ball State University has been teaching and developing the components of Mobile GIS in its Computer Geo-Science, GPS Techniques, and Field Camp courses, and will be incorporating them into Structural Geology. Typically, an introductory one-hour class session is held in the field to teach acquiring GIS data. The next step is a two-hour class to teach map creation using a laptop based GIS program (ArcMap). The students are then asked to independently acquire more geologic data such as outcrop locations, rock descriptions, and strike/dip; transfer the data to a laptop; generate a final map using GIS; and print the product within a week.

We have integrated Mobile GIS into our traditional geologic mapping exercises, as well as developed new, GIS-specific exercises. Since the bedrock in east central Indiana is topographically invariant, non-inclined, and often not exposed, here we present our new concept for an introductory project. 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. The students record a rock description and strike/dip as a data point which is GPS-located on the PDA, and construct a geologic map with this information. This exercise challenges students to use higher order thinking skills needed in generating a geologic map while providing the benefits of the spatial organization and data availability of Mobile GIS in the field. It also prepares students to use GIS technology during advanced classes held in the more complex settings of the Appalachians and Wyoming.