The MayaArch3D project: A 3D WebGIS for analyzing ancient architecture and landscapes

There is a need in the humanities for a 3D WebGIS with analytical tools that allow researchers to analyze 3D models linked to spatially referenced data. Geographic Information Systems (GIS) allow for complex spatial analysis of 2.5D data. For example, they offer bird’s eye views of landscapes with extruded building footprints, but one cannot ‘get on the ground’ and interact with true 3D models from a pedestrian perspective. Meanwhile, 3D models and virtual environments visualize data in 3D space, but analytical tools are simple rotation or lighting effects. The MayaArch3D Project is developing a 3D WebGIS—called QueryArch3D—to allow these two distinct approaches to ‘talk to each other’ for studies of architecture and landscapes—in this case, the eighth-century Maya kingdom of Copan, Honduras. With this tool, researchers can search and query, in real time via a virtual reality (VR) environment, segmented 3D models of multiple resolutions (as well as computer-assisted design and reality-based) that are linked to attribute data stored in a spatial database. Beta tests indicate that this tool can assist researchers in expanding questions and developing new analytical methods in humanities research. This article summarizes the results of a pilot project that started in 2009, with an art historian and an archaeologist’s collaborative research on the ancient Maya kingdom and UNESCO World Heritage site of Copan in Honduras—called MayaArch3D. The project researches inno736 digitalcommons.unl.edu T h e M a y a a r c h 3D p r o j e c T : 3D W e b GIS f o r a n c I e n T a r c h I T e c T u r e a n D l a n D S c a p e S 737 1 The Gap between GIS and 3D Modeling Systems 1.1 3D modeling Modern sensor and computing technologies are changing the practice of art history and archaeology because they offer innovative ways to document, reconstruct, and research the ancient world in 3D (El-Hakim et al., 2008; Reindel and Wagner, 2009). State-of-the-art imaging technologies allow researchers to document 3D objects to the level of the micron (e.g. Grün, 2008), whereas Virtual Reality (VR) simulation programs enable reconstructions of ancient buildings in their ancient environments and landscapes. However, as Frischer has noted (2008), the perception is that 3D models are purely illustrative—ideal for education or conservation— whereas how 3D models can assist with comparative research on architecture is an ongoing question. Since 1998, Jennifer von Schwerin has addressed this question for ancient Maya architecture when she began collaborating with Harvard University archaeologists to analyze the collapsed façade sculpture of an eighth-century temple at Copan, Honduras, called Temple 22 (Ahlfeldt 2004; Fash 2011b; von Schwerin 2011a). As an art historian, von Schwerin seeks to correlate political and social changes in ancient Maya kingdoms with developments in architectural form over space and time. But the first challenge is simply to bring together data on the temple that is spread around the world in various archives and museums and to determine how the building once appeared in the past. To test her reconstructions, von Schwerin turned to digital 3D tools. Different methods are possible for creating 3D models of ancient monuments—such as computer graphics, procedural modeling (models created from sets of rules), and reality-based modeling (models created from real-world data such as laser scanning)—and increasingly, these are being combined to create multi-resolution 3D reconstructions. Although this combination can expand research possibilities, it is critical to identify optional modeling techniques based on researcher needs and to define the workflow for dealing with multi-resolution models in a 3D WebGIS tool. The MayaArch3D project is addressing this by creating test data of multi-resolution 3D models from Copan, including various 3D simulations of Temple 22 (Remondino et al., 2009, von Schwerin et al., 2011b). The 3D models are being generated at different levels of detail (LoD) and resolutions ranging from individual buildings to archaeological complexes using methodologies based on image data acquired with passive sensors (e.g. digital cameras), range data acquired with active sensors (e.g. laser scanning), classical surveying, and procedural modeling using existing maps. The choice depends on the required accuracy, object dimensions and location, the surface characteristics, the team’s level of experience, the project’s budget, and the final goal. For example, computer-assisted design (CAD) models such as the 3D Studio Max model of Temple vative approaches to integrate GIS, 3D digital models, and VR environments online for teaching and research on ancient architecture and landscapes. It has grown into an international, interdisciplinary project that brings together art historians, archaeologists, and cultural resource managers with experts in remote sensing, photogrammetry, 3D modeling, and VR. The Start Up Phase was funded by two National Endowment for the Humanities, Digital Humanities Start-Up grants to the University of New Mexico (PI: Jennifer von Schwerin) and developed and beta tested a pipeline and prototype 3D WebGIS—called QueryArch3D. The prototype version is available at http://Mayaarch3d.org/project-history/). Project results indicate that it is possible to bridge the gap between 3D and GIS to create a resource for researchers of Maya architecture to compare and analyze 3D models and archaeological data in the context of a geographically referenced, VR landscape. 738 v o n S c h W e r I n e T a l . I n L i t e r a r y a n d L i n g u i s t i c c o m p u t i n g 28 (2013) 22 depicted in Figures 1 and 2 offers the ability to test hypothetical reconstructions and to analyze a building from multiple perspectives (e.g. bird’s eye, exterior versus interior view) with rotation or lighting effects (Figure 3).1 Reality-based models created using active and passive sensors allow for comparison against CAD reconstructions (Figs 4 and 5). VR such as this low-resolution SketchUp model of Copan’s landscape (Figure 6)—created using georeferenced building footprints—provides an urban context for high-resolution 3D models of individual structures and allows users to virtually navigate through ancient cities and landscapes and to increase their awareness of mass, space, and spatial relationships. This interaction facilitates a sense of embodiment and place (Forte and Bonini, 2010), and it also is useful for visualizing the results of archaeological research—for example, an affiliated project is working to display the results of archaeoastronomical studies at Copan (see Figure 10). These are just a few reasons that counter the common perception that 3D models are purely illustrative (e.g. Frischer and Dakouri-Hild, 2008). Increasingly, projects are demonstrating the value of 3D models for scientific analysis. Researchers developing tools for viewing and analyzing sophisticated 3D architectural models include the two big VR environment re-creation laboratories—the Experimental Technology Center at University of California, Los Angeles and the Institute for Advanced Technology in the Humanities at the University of Virginia, who have collaborated on the project ‘Rome Reborn’ (romereborn.frischerconsulting.com). In Europe, 3D models of architecture are used to analyze building plans and phases [for instance, the projects on Roman emperor palaces in Rome and Serbia (Weferling et al., 2001) and analyses of the Cologne cathedral (Schock-Werner et al., 2011)]. More recently, a few researchers have begun to explore how digital models might be used for comparative online research. One example is Stephen Murray’s “Mapping Gothic France” project—a collaborative project linking text, Quick Time VR, and 2D and 3D images to an interactive map of Gothic cathedrals. One promising opportunity—the approach taken by the MayaArch3D Project—is to use 3D models as visualization “containers” for different kinds of information (Manferdini et al., 2008). These recent advantages have initiated a broader interest in 3D modeling for archaeology and cultural heritage, which is evident at conferences such as CAA Figure 1. The 3D low-resolution CAD model of Temple 22 used for testing hypothetical reconstructions integrated with high-resolution reality-based 3D models of architectural sculpture (3D model created by F. Galezzi) Figure 2. Preliminary high-definition model of Temple 22 used to test the process of integrating various data sources into the reconstruction process. (3D model by R. Maqueda and J. von Schwerin) T h e M a y a a r c h 3D p r o j e c T : 3D W e b GIS f o r a n c I e n T a r c h I T e c T u r e a n D l a n D S c a p e S 739 (Computer Applications and Quantitative Methods in Archaeology), CIPA (International Committee for Documentation of Cultural Heritage), and the recently founded peer-reviewed journal Digital Applications in Archaeology and Cultural Heritage. 1.2 3D models in ancient American archaeology Most applications of 3D archaeology focus on archaeological sites in Europe or the Middle East; however, the acquisition of reality-based data for 3D models also is increasing for the archaeology of the ancient Americas (e.g. Reindel and Wagner, 2009; Lambers et al., 2007). As for current 3D projects that deal with the remains of the ancient Maya specifically, some are engaged with high-resolution scanning of individual sculptures for conservation and analysis and are considering ways to offer them online. These include Harvard University’s Corpus Project (Tokovinine and Fash, 2008; Fash 2011a, 2012), the MayaArch3D Project summarized here (see also Remondino et al., 2009), and the Mesoamerican Three-Dimensional Imaging Database (Doering and Collins, 2009) (http://www.famsi.org). Other web-based applications, like CyArk, use Google Earth and make point clouds available of whole Maya structures (http://archive.cyark.org). Meanwhile, so