From characterizing groundwater resources, to evaluating landslide susceptibility, to characterizing the impacts of storm events like Tropical Storm Irene, Green Mountain College uses geologic mapping to study, explore, and evaluate many environmental issues in Vermont.

Green Mountain Landscape

A Rocky Proposition

Traditional mapping techniques make use of paper maps, a field notebook, camera, and handheld GPS. In an effort to streamline this process over the last decade I have moved from an inexpensive consumer grade Garmin, to the Trimble GeoXT and the Trimble Juno, to Collector for ArcGIS running on an iPad mini. Many of these options still required paper maps, external camera or additional software to create data dictionaries. This summer I tested Fulcrum while mapping the surficial geology of Monkton, Vermont and I believe it combines all the needs of traditional mapping within a single interface.

Maintaining Lateral Continuity

The browser-based Fulcrum interface allows for easy creation and management of a database with required fields and visibility rules that can control input and maintain data consistency across multiple users. Beyond the obvious advantage of eliminating the need for additional software, this means that state surveys, consulting firms, and students working on group projects can save time at the end of a project by not having to merge data with different field names, formation abbreviations, etc.

For example, in Figure 1 below, visibility is based on whether the user selects Field Site, Bedrock Exposure, Ice Direction, or Mass Wasting under the Type option. If the user selects Field Site they are prompted to choose from a list of surficial units and if they select Ice Direction, they are required to input an azimuth value (Figure 2). Depending on the project these required fields could include strike, dip, trend, plunge, grain size, biomarkers, etc. In addition to adding multiple photos to any location, you can also enter field notes in the description field or use one of the many options for annotating photos — for example Skitch — and add them to any field site. I also used the Theodolite app to take photos of exposed sediments to capture their approximate dip within the photo (Figure 3).

Image of structure for surficial geologic mapping Figure 1: Example structure for surficial geologic mapping. Vertical red bars indicate required fields and vertical blue bars indicate their visibility is inherited from the user selection.
Image of required fields Figure 2: Example interface illustrating how required fields and visibility rules can improve data consistency across multiple users.
Using Theodolite for dip measurement Figure 3: Example image taken with the Theodolite app recording approximate dip of delta foresets.

Stratigraphy of Data

In addition to keeping data structure consistent, users are able to add their own layers and download them for offline use. This is one of the most useful tools in Fulcrum for geologic mapping because you can include any map you would normally carry in paper format and visualize field relationships across multiple overlays. For example in the Monkton app I added a slopeshade derived from high-resolution LiDAR and a shapefile depicting the spatial extent of Pleistocene glacial lakes in the area (Figure 4). This allowed me to juxtapose these two layers during field transects and more accurately delineate boundaries between lake bottom lake clays and glacial till on valley slopes. Other useful layers might include topographic maps, well locations, known faults, gravel deposits, etc.

Accessing all your data within the browser also offers access to high-resolution imagery from Mapbox or user uploaded imagery. The benefit of this feature is you can digitize features directly within the browser and create new points and maintain consistency within the database, rather than digitizing features in a GIS and then merging data. For the Monkton project I made use of the Mapbox Satellite imagery to digitize additional exposed bedrock that will later be used with well data to interpolate a derivative surficial overburden map (Figure 5).

Image of LiDAR-derived terrain overlay Figure 4: Screenshot illustrating the use of a LiDAR-derived terrain overlay to help visualize field relationships.
Image of digitized bedrock exposures Figure 5: Screenshot illustrating the use of Mapbox Satellite imagery to digitize bedrock exposures.

Embrace The Cloud

One concern I often hear about moving away from paper notebooks or maps is the perceived disaster of losing or submerging an electronic equivalent. After a summer of carrying my iPhone through wetlands, across streams and working through rainy days I feel confident that this is a safer way of storing data. Even when I got trigger happy with the camera I was still able to backup my data in the field over 4G and occasionally LTE. So worst case scenario, I would have lost a day of work rather than the entire season in a single notebook.

“Fulcrum allows me to carry a topographic map, LiDAR derived terrain, high-resolution imagery, previously collected field data, a notebook, camera, inclinometer, and a GNSS/GLONASS enabled GPS within a single device that’s tied to the cloud.”

From an educational perspective, Fulcrum offers students the ability to build an app the entire class brainstorms or to create their own, which could then be tested and compared with apps created by their peers. This provides an alternative to less intuitive GIS or GPS software and allows students to focus on what type of data should be collected and how to create an app that requires users to comply with their data requirements. This does assume access to a GPS-enabled phone or tablet, which are still less expensive than many common GPS units used in geologic mapping.