Visualization and Sharing of 3D Digital Outcrop Models to Promote Open Science Visualization and Sharing of 3D Digital Outcrop Models to Promote Open Science
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25–28 Oct. GSA 2020 Annual Meeting VOL. 30, NO. 6 | JUNE 2020 Visualization and Sharing of 3D Digital Outcrop Models to Promote Open Science Visualization and Sharing of 3D Digital Outcrop Models to Promote Open Science Paul Ryan Nesbit, Adam D. Boulding, Christopher H. Hugenholtz, Dept. of Geography, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada; Paul R. Durkin, Dept. of Geological Sciences, University of Manitoba, 66 Chancellors Circle, Winnipeg, Manitoba, R3T 2N2, Canada; and Stephen M. Hubbard, Dept. of Geoscience, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada ABSTRACT INTRODUCTION opportunities to analyze and revisit data at High-resolution 3D data sets, such as High-resolution 3D digital models are multiple scales. Open source programs, digital outcrop models (DOMs), are increas- becoming increasingly common data sets in such as Blender and CloudCompare, can be ingly being used by geoscientists to supple- academic and commercial applications. In used for data exploration and measurement ment field observations and enable multi- the geosciences specifically, digital outcrop and have also integrated specific geosci- scale and repeatable analysis that was models (DOMs), or virtual outcrops, can ence toolsets (e.g., Brodu and Lague, 2012; previously difficult, if not impossible, to provide geoscientists with photorealistic Dewez et al., 2016; Thiele et al., 2017). achieve using conventional methods. De- models that preserve spatial precision, Although acquiring DOMs has become spite an increasing archive of DOMs driven dimensionality, and geometric relationships more straightforward, and various 3D analy- by technological advances, the ability to between geologic features that are inherently sis programs are available, dissemination of share and visualize these data sets remains 3D and susceptible to distortion and/or loss DOMs, interpretations, and results has a challenge due to large file sizes and the of information when rendered in 2D (Bellian remained a challenge due to software and need for specialized software. Together, et al., 2005; McCaffrey et al., 2005; Jones et file-size barriers. Specialty 3D programs are these issues limit the open exchange of data al., 2009). Digital 3D mapping approaches often hindered by product licensing and can sets and interpretations. To promote greater using DOMs have enabled geoscientists to involve a considerable learning curve to data accessibility for a broad audience, perform supplemental measurements, corre- understand controls, file formats, and inte- we implement three modern platforms for lations, and interpretations that are difficult grated tools. Furthermore, DOMs can easily disseminating models and interpretations or impossible to obtain with traditional meth- exceed multiple gigabytes (GB) in size, within an open science framework: Sketch- ods (Figs. 1–2; Pavlis and Mason, 2017; Nes- which can be taxing on computational fab, potree, and Unity. Web-based plat- bit et al., 2018). resources for rendering, file storage, and forms, such as Sketchfab and potree, render Until recently, however, collection and data transfer. With the growing collection of interactive 3D models within standard use of digital data sets has been limited to high-resolution DOMs and similar 3D data web browsers with limited functionality, specialists, due to hardware and software sets, there is a need for dedicated, intuitive, whereas game engines, such as Unity, limitations. A number of methods are now and accessible 3D visualization platforms. enable development of fully customizable available for collecting and processing 3D Given the challenges outlined above, we 3D visualizations compatible with multiple models (Hodgetts, 2013; Carrivick et al., examined existing visualization solutions operating systems. We review the capabili- 2016). In particular, structure-from-motion that could potentially enable sharing of ties of each platform using a DOM of an and multi-view stereo (SfM-MVS) photo- DOMs and support open science through extensive outcrop exposure of Late Creta- grammetry software, commonly paired increased data accessibility. To provide a ceous fluvial stratigraphy generated from with uninhabited aerial vehicles (UAVs), functional introduction to modern visualiza- uninhabited aerial vehicle images. Each enables geoscientists to produce photoreal- tion platforms, we illustrate the capabilities visualization platform provides end-users istic DOMs through a highly streamlined and functionality of two web-based inter- with digital access and intuitive controls to UAV-SfM workflow (Chesley et al., 2017; faces (Sketchfab and potree) and a cross- interact with large DOM data sets, without Nieminski and Graham, 2017; Pavlis and platform videogame engine (Unity) using a the need for specialized software and hard- Mason, 2017; Nesbit and Hugenholtz, 2019). geologic case study. A DOM was produced ware. We demonstrate a range of features Related efforts have centered on the through a UAV-SfM workflow for an exten- and interface customizability that can be development of 3D software solutions with sive outcrop (1 km2) exposed within the bad- created and suggest potential use cases tools for geoscience applications. Custom land landscape of Dinosaur Provincial Park to share interpretations, reinforce student software packages, such as Virtual Reality (Alberta, Canada). Each visualization plat- learning, and enhance scientific communi- Geology Studio (VRGS; Hodgetts et al., form provides access to the large DOM cation through unique and accessible visu- 2007) and LIME (Buckley et al., 2019), through an intuitive lightweight interface alization experiences. offer users lightweight executable tools and without the need for high-end hardware, GSA Today, v. 30, https://doi.org/10.1130/GSATG425A.1. Copyright 2020, The Geological Society of America. CC-BY-NC. N channel-belt deposit E accretion w leoo 2 m paleoopa channel-belt base oodplain mudstone channel-belt base Figure 1. Geologic interpretations (line drawing on 2D field photograph), a common conventional method to highlight stratigraphic architecture and distri- bution of related units. Mudstones are gray to light brown; sandstones are light gray to white. This process is often performed on photos or a photomosaic acquired in the field. meander-belt edge ALBERTA Figure 2. Traditional geologic map used to share field measurements, observations, and interpretations in 2D plan-view. This geologic map Dinosaur was constructed from the integration of traditional fieldwork methods Provincial (measured sections as well as paleoflow and bedding measurements) Park with digital outcrop model mapping to characterize heterolithic chan- 111.59º W nel-belt deposits exposed at Dinosaur Provincial Park, southeastern Alberta, Canada. Field-based Facies Associations (FA)1—sandy point 50.82º N bar; FA2—heterolithic point bar; FA3—Counter-point bar; FA4—aban- doned channel; FA5—mudstone. Bedding surfaces, noted in Figure 1 Extent of g. 1 (red), were digitally mapped on the 3D model and yield a more refined 3D model Fi and detailed interpretation of accretion surface orientation and strati- graphic architecture. These methods are being widely applied, yet the Measured results are difficult to disseminate and share in 3D. section Strike/Dip of bedding N Interpreted 200 m scroll pattern FA1 FA2 FA3 FA4 FA5 specialized software, or transfer and storage bottlenecks remain, with a lack of accessible issues relative to underlying base layers of large files. This prompts an increased visualization software and the need to trans- (Tavani et al., 2014). ability to share data sets, interpretations, and fer large files. Web-based dissemination may be one of results with a wider community, expanding Though separate 3D viewers are available the most promising and practical means for opportunities for scientific communication to supplement proprietary software (e.g., rapidly streaming 3D digital data sets with- and open science education. Trimble RealWorks, FugroViewer), they typ- out transferring raw data (Turner, 2006; von ically require local storage of large files, Reumont et al., 2013). Advances of applica- RELATED WORK learning curves, and have associated licens- tion programming interfaces (APIs), such as Visualization of digital 3D models has ing restrictions. Alternative applications, WebGL, allow modern Internet browsers to been practical for more than two decades; such as digital globes (e.g., Google Earth) are access the local GPU to improve rendering of however, early geoscience applications were a popular method for disseminating spatial 2D and 3D graphics, without the need for typically restricted to dedicated geovisual- and non-spatial data in an interactive, semi- plug-ins or extensions (Boutsi et al., 2019). ization labs and required specialized soft- immersive environment, with intuitive con- Though not guaranteed, WebGL enables ware (e.g., Thurmond et al., 2006; Jones et trols (Goodchild et al., 2012). Digital globes GPU functionality on various operating sys- al., 2009; Bilke et al., 2014). Today, visual- have been used to create “virtual field trips” tems and devices (Schuetz, 2016). Several ization of large 3D data sets is no longer lim- (McCaffrey et al., 2010; Simpson and De proprietary web viewers, such as Sketchfab ited to sophisticated labs, but rather an aver- Paor, 2010; De Paor and Whitmeyer, 2011) (https://www.sketchfab.com), use WebGL age computer can render 3D models ef- and