KEEPING YOUR EYE ON THE PRIZE - DIGITAL BEDROCK GEOLOGIC MAPPING TECHNIQUES IN THE EASTERN REGION OF THE USGS

The goal of digital field data capture for our geologic mapping is to obtain well-attributed, accurately georegistered data at 1:24,000-scale for export to ArcGIS. Testing and modification of digital methods over more than two decades have enabled USGS geologists to streamline methods of data capture in the field, and improve efficiency in creating maps. Digital techniques inevitably become obsolete, and so it is beneficial to test new devices and modify procedures in order to continually evaluate what works best. The ultimate goal is to publish a peer-reviewed, scientifically sound and cartographically accurate map and database, and it is increasingly necessary to have skills covering geographic information systems (GIS), digital cartography, and information technology (IT) — skills not traditionally associated with geology.

We employ a variety of hardware and software in the field including iPads and iPhones running iGIS, ruggedized Windows tablets running FieldMove, and Garmin, Trimble, and Dual Bluetooth-connected GPS receivers. The benefits include not only more accurate data collection, but also visualizing available geologic, planimetric, and hypsographic data in real-time. Field use of high-resolution aerial imagery and LIDAR-derived DEM basemaps is practical only with digital devices. Exploration of field data, geotagged photos, geophysics, and imagery improves field mapping. Data are managed in ArcGIS, Global Mapper, Google Earth, and EarthVision for 2D and 3D presentation. Distribution of GIS databases in shapefile and KML formats is the norm, but our varied collection and compilation methods are trending toward populating a standardized data model known as NCGMP09. We employ Adobe Illustrator at various stages of the digital cartographic process. The aim is to maximize the efficiency of our workflow by examining where problems occur, and explore the technological possibilities to help us improve the process. Our use of multiple, ever-changing tools allows a fusion of techniques tailored to the preferences of the individual field geologist, while at the same time keeping the standardized, high-quality published map as the ultimate goal of all mapping projects.