THE EVOLUTION OF FIELD MAPPING AND DATA COLLECTION: FROM PAPER TO DIGITAL AND BEYOND

Geological research and education has a long and robust history rooted in fieldwork and field observations. William Smith (ca. 1815) essentially created the traditional presentation format for geologic maps, where surface patterns of stratigraphic units are represented by colored regions on a paper map, and subsurface interpretations are shown on associated cross-sections. With few exceptions, the methods of field data collection and map presentation changed very little during the 19^th and 20^th centuries. However, during the past decade geoscience fieldwork and mapping have undergone a major change in methodologies, largely precipitated by GPS- and GIS-equipped mobile computers paired with virtual globe visualizations. Ruggedized mobile PCs can record a wide spectrum of geologic data and facilitate iterative map construction and evaluation on location in the field. Spatial data and interpretations can be presented interactively on virtual globes, such as Google Earth.

We present examples of modern approaches to fieldwork and the advantages and disadvantages of digital equipment and software, with a specific focus on Google Earth-based geologic maps. Interactive features of these maps include: 1. The ability to zoom, pan, and tilt the maps to any desired viewpoint; 2. Selectable polygons of geologic units that can be rendered semi- or fully-transparent, allowing the viewer to examine the underlying terrain; 3. Structural symbols (e.g., strike and dip) positioned at outcrop locations, which can display associated metadata; 4. Serial cross-sections positioned precisely over the associated geologic map; and 5. Other data, such as digital photos or sketches, as clickable, zoomable objects at their correct field locations. These interactive features allow users not only to view geologic maps and cross-sections in a virtual 3-D environment, but also to examine the original field data on which the map interpretation is based. As such, digital field and mapping methods allow geoscientists to combine the previously disparate components of field measurements, notes, sketches, photos, maps, and cross-sections into an integrated and easily accessible package.