GEOLOGIC FIELD MAPPING WITH TABLETS: VALUABLE TOOLS WITH ROOM FOR IMPROVEMENT

Tablet computers have become essential equipment for many field geologists, and recent studies demonstrate that iOS devices in particular are suitable for measurements typically done with a Brunton compass. GPS located observations visible on base data that can be toggled between imagery, lidar, and existing geologic data, combined with rapid collection of structural orientations greatly enhances the efficiency and efficacy of any mapping effort. However, these helpful devices are only as good as the mapping applications available. Geologists at NBMG have incorporated iOS tablets into our field mapping procedures, with heavy use of three apps in particular: Avenza Maps, Field Move, and TouchGIS. As is common throughout the geological sciences, our final geologic maps are drafted in ArcGIS, therefore functional data transfers between the tablet and Arc is important. The experience of working with these products has allowed us to distill the criteria we believe are most critical for a mapping app. The most basic feature is utilizing the tablet’s GPS to make point based field observations with accompanying geotagged photos. Location based structural orientation measurements is another critical data collection capability. Streaming basemaps including imagery and elevation data that can be cached for offline use is a helpful utility. In addition, apps should have the functionality to import georeferenced raster data exported from desktop mapping software, such as lidar derivatives and custom geologic maps. Ideally the raster data can be imported using formats with compact data size such as geospatial pdfs. Field observations need to be easily transferred from the tablet to desktop computers, likewise exported ArcGIS linework should be easily transferable to the app. Data transfer via cloud-based data storage sites is preferable, but a hardline transfer option is important. Finally, with tablets and their operating systems constantly being updated, apps need to be regularly maintained by the developer to be a stable platforms with any longevity. Although each of the tablet apps listed above do some of these features well, none currently cover all of these functions. In the future, a single tablet software package that can accomplish all of these essential features would greatly benefit the geoscience community.