USING THE ESRI COLLECTOR APP FOR GEOLOGIC MAPPING—A MOSTLY GOOD EXPERIENCE

Over the past three field seasons we have been conducting geologic field mapping using an Apple tablet and Esri’s Collector app. This process has simplified field data collection by reducing the number of tools required to do fieldwork, reducing the amount of paper required to be brought in the field, streamlining map manipulation and edits between field visits, reducing post-fieldwork data input and processing time and the potential errors that are commonly introduced during that process, and increasing competency and efficiency in the field by showing a real-time GPS location on a geo-located raster basemap. The Collector app meets our needs by functioning offline, collecting line and point data, geotagging and attaching field photos to points, allowing custom symbolization and proper rotation of attitude data, allowing custom raster basemaps to be used offline, and streamlining data input to an Esri desktop environment. However, the Collector app lacks the ability to use complex symbology for lines (i.e., ball and bar of a normal fault) and the line editing functions are generally cumbersome, simplistic, and inefficient. The Apple tablet has proved to be a lightweight, relatively inexpensive, durable piece of hardware that has a battery life capable of a full day of fieldwork and has an integrated GPS with location accuracy comparable to a recreational-grade handheld GPS unit. Matte tempered glass or film screen covers are the best way to reduce screen glare on field tablets but both options are a compromise in durability and protection compared to hard plastic.

Although the use of digital compasses for attitude data collection is on the rise, we are not currently using the tablet to collect such data. Preliminary tests of the digital compass on an iPad resulted in an average of 53 degrees of deviation in azimuth from a traditional Brunton compass. Many factors could contribute to this high deviation so until we have collected a more robust dataset, we will continue to experiment with digital compasses but rely on our Brunton compasses. Another limiting factor of collecting digital attitude data is lack of integration of a digital compass tool within the Collector app. Until such a tool becomes available within the Collector app, using a traditional Brunton compass is equally time efficient and likely more precise and accurate.