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from 2D sources. It is largely for this rea- cameras for SfM work. The resultant how these techniques can aid learning
son, and the spatial error issues in the 2.5D data could be used to obtain a true bare- rather than hinder it.
method, that most 3D geologic modeling to ground model with no questions on
date has been limited to the relatively sim- potential filtering artifacts that can arise Finally, many have lamented the decline
ple visualizations of flat-lying to nearly from conventional airborne LiDAR. of field geology, yet at the same time blame
flat-lying strata or simply deformed rocks Alternatively, this application could be high-tech for this decline (e.g., Callan,
(e.g., MacCormack et al., 2015). used as a simple outcrop finder tool in 2016). Our experience is the opposite.
areas of poor exposure. Specifically, paper-based field geology
At present, workflows for both 3D map- 4. The expansion of cheaper and lighter- using nineteenth-century technology is
ping and 3D model construction are depen- weight multi- and hyperspectral sensors viewed by most modern students as “old
dent on software that is neither customized for UAS and the improvement of com- school,” and many shy away from field
for the field environment nor readily mercially available UAS to more easily studies as a result. Incorporation of digital
amendable to the limitations of field com- integrate with these sensors (e.g., see mapping and these 3D techniques, how-
puters. Nonetheless, given the speed of Buckley et al., 2016) will potentially lead ever, excites modern students and has the
development of software and hardware, to a geologist’s ability to develop 3D litho- potential to attract a whole new generation
this limitation will be trivial within the logical classification maps in the field— of tech-savvy field geologists who could
next two to three years, suggesting that all essentially giving field geologists live, solve problems previously considered
of these capabilities will be readily avail- multispectral eyes. As of yet, studies with impossibly complex.
able for field geology, if we choose to multi- or hyperspectral cameras on UAS
embrace them. have been limited, with few applications CONCLUSIONS
to bedrock geology (e.g., Buckley et al.,
Near Future Capabilities and the 2016). In the United States this is likely Three-dimensional terrain models
Importance of UAS due to the previously strict Federal derived from SfM, particularly when aug-
Aviation Administration UAS regulations mented with aerial photography from
Another technology, unmanned aircraft as well as the high cost of these sensors, UAS, provide an inexpensive base for the
systems (UAS), promises to expand 3D but experiments of this type clearly are next generation of geologic mapping using
mapping further in ways we undoubtedly ongoing in Europe (Buckley et al., 2016). a 3D interface. Visualization of these mod-
do not yet fully grasp. UAS have become a In addition, the current commercially els frees geologists from the confines of
prominent topic across society, and their available sensors for UAS only provide flat maps and allows high-precision map-
proliferation offers huge opportunities for visible and near infrared (VNIR) ping of steep slopes and cliffs, which are
field geologists (e.g., Hugenholtz et al., imagery/data designed for agricultural virtually invisible in conventional maps.
2013; Bemis et al., 2014; Jordan, 2015; purposes (Link et al., 2013; Herrero- The ability to easily examine multiple
Hackney and Clayton, 2015). They already Huerta et al., 2014; Rasmussen et al., view angles of Earth’s 3D surface outside
serve as aerial platforms to enhance con- 2016) or thermal infrared (TIR) for the time limitations and logistical con-
struction of SfM models. However, there disaster management, monitoring geo- straints of fieldwork is a cognitive break-
are many opportunities beyond this appli- thermal environments, etc. (Nishar et through that frees field geology from the
cation. Some examples include al., 2016; Yahyanejad and Rinner, 2014), one-site–one-visit paradigm. Many geolo-
1. A low-cost, lightweight drone that could while lithology is best distinguished with gists have lamented the decline of field
shortwave infrared (SWIR). geology, but the rise of these 3D technolo-
become every geologist’s “field assis- Beyond these drone-based applications, gies has a potential to revitalize field geol-
tant,” with tasks ranging from safety to perhaps the biggest advances will come ogy and launch a new generation of studies.
planning (e.g., applications as simple as from full 3D visualization and mapping Research is desperately needed, however,
route planning to as complex as geologic capabilities in software in the field envi- on ideal workflows that employ this tech-
recon or hazard assessment). ronment. Virtual reality (VR) headsets are nology across a range of applications and
2. A drone with a remote video feed becoming more readily available and could the range of field sites, and perhaps most
equipped with a suitable magnetometer- be used in a field scenario to produce a 3D importantly, how this technology can aid
accelerometer system and an ability to representation of a scene in front of the 3D learning rather than hinder it.
orient the device remotely could gather geologist, potentially complete with multi-
remote orientation measurements from spectral 3D renderings, providing an aug- ACKNOWLEDGMENTS
cliff faces or inaccessible terrain. To our mented reality interface that would allow
knowledge no such device yet exists, but resolution of features undreamed of, even We thank L. Serpa, J. Brush, and J. Hurtado for
is possible with modern technology. now. Perhaps most important, however, is input on this effort and two anonymous reviewers
3. A major advance in geomorphology the potential of this technology to teach and GSA Today editor G. Dickens who provided
arose with bare-ground models obtained concepts to the next generation of students helpful input on the original manuscript. We thank
by filtering airborne LiDAR data (e.g., at all levels. Freed from the confines of flat Midland Valley Ltd., Maptek Ltd., and Leapfrog
Haugerud et al., 2003). A drone maps, there is a potential for accelerated Ltd. for software donations that aided this study.
equipped with an object-avoidance sys- learning of 3D concepts using this technol- This work was supported by NSF EAR-1250388.
tem, such as an optical proximity mea- ogy. Nonetheless, research is needed on
surement tool, could be developed to fly REFERENCES CITED
through a forested area below treetop
level carrying a LiDAR system and Bemis, S.P., Micklethwaite, S., Turner, D., James,
M.R., Akciz, S., Thiele, S.T., and Bangash, H.A.,
2014, Ground-based and UAV-based photo-
grammetry: A multi-scale, high-resolution
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