Technology in Archaeology
Technology in Archaeology
The Archaeology and Research Laboratory (A&R) is part of the Historic Preservation Office (THPO) of the Confederated Tribes of Grand Ronde (CTGR). Part of tA&R’s mission is to develop and communicate new research methods that center CTGR perspectives and values. Over the past several years, A&R has been exploring “digital twinning” as a way to record, preserve and engage with historical and cultural resources. A digital twin is a digital model or representation of a real-world physical object, place, person, or system. The method was first used in engineering to create a model of a product or system for simulation, and testing, prior to real world development implementation. A&R uses digital twins to map, manage, and communicate the importance of cultural resources to planners, agencies and members of the tribal community.
Depending of the situation, A&R creates digital twins using several different technologies including: Geographic Information Systems (GIS), Photogrammetry, LiDAR Scanning and Ground Penetrating Radar (GPR).
Geographic information systems
The most basic digital twin is a database: a collection of attributes (shape, size, color, age associated practice etc.) of a cultural resource. A&R developed several databases to house different types of data, and uses mapping programs on tablets to access existing data in the field—including old photographs, maps and object locations and descriptions. The same program was used to create digital forms to record data in the field that can be viewed in real time by staff back in the office.
Photogrammetry: A&R creates Photogrammetry models of objects, structures, and landscapes. using handheld cameras, tablets or UAVs (drones). By taking a series of overlapping photos, we can use software to generate a 3D model of the object. Sometimes as little as 20 to 30 photos are enough to create a photogrammetry model. For buildings and landscapes, hundreds or thousands of photographs may be needed.
LiDAR Scanning: Light Detection and Ranging (LiDAR) is a remote sensing technique that emits light from a laser to measure ranges from the source to an object (and back) to generate 3D renderings of physical space. This is another method that the AnR Program utilizes within archaeological investigations and building scanning. LiDAR, as a method, is highly precise for situations when accuracy is needed.
AnR has been testing the capabilities of using LiDAR featured in iPads for data collection. The results can then be tested against other (more expensive) sensors to evaluate cost versus accuracy tradeoffs. So far the program has been able to capture buildings as well as objects quickly and with high accuracy.
Ground Penetrating Radar(GPR): Uses electromagnetic waves to detect reflection of the signal off of subsurface features, further enriches data, and archaeological reconstructions.
Ground Penetrating Radar (GPR) is a technique that shoots a pulse or wave of electromagnetic energy into the ground and then records how much of the wave is reflected back to a sensor and how long that wave takes to travel. From this, GPR allows us to detect or “see” objects below the surface of the ground.
However, what GPR “sees” are differences in how reflective something is to a radar pulse. Metal is highly reflective(or bright), as is the surface of water. Dry sand/silt are less reflective and show up as "dark". If most of the GPR pulse is reflected by an object, it is difficult if not impossible to see what is below that object. GPR is also highly sensitive (it can pick up the energy from a cell phone call) and local conditions like soil moisture, and metal buildings can interfere with the instrument. A&R uses GPR regularly to identify buried resources with no or minimal excavation.
1880s Woolen Mill: Documenting Potential Archaeological Features These different technologies can be brought together to create digital twins that reflect several different types of data. Grand Ronde’s tumwata Village property in Oregon City has a complex history and archaeology which includes thousands of years of occupation by Grand Ronde ancestors and 170 years of colonial presence. This history has left an archaeology that includes standing walls and foundations from 19th and 20th century buildings and below ground archaeology.
As part of an ongoing project, A&R is creating a digital twin of a decade-old excavation in the Oregon City Woolen Mill by integrating:
-LiDAR scans conducted with an iPad
-GIS models of ten-year-old excavation records
-Models of georeferenced GPR data
This construction through scans, excavation notes, and GPR made it possible to analyze the relationship between the standing ruins and potential underground features. The results from this investigation will help guide future archaeological work at the Woolen Mill.
Utilizing LiDAR and photogrammetry to make a digital twin of tumwata Village has allowed the Tribe to plan for and incorporate historic elements of tumwata Village into their design plans for the site. Using digital twinning techniques on this project, and other, have allowed for a balance of management and preservation, while developing new, integrated methodologies for the archaeology of the site.
Interpretation & Perspectives
A&R’s use of digital twinning is more than making “pretty pictures”. These mapping and data capture techniques are important for other tasks our office is responsible for including:
National Register of Historic Places recording by scanning buildings to include the models in documentation.
Archaeological Excavations to show changes within sediments across different units of the same site as they are excavated. Bring People to Place and Time through
Immersive Experiences (AR / VR) or video.
Historic Photographs & 3D Interpretation
A&R has begun development of very simple immersive experiences. Using the program ArcGIS Pro and collections of historic photographs, we are creating 3D models of buildings that no longer exist. If the former location of the building is known, and if there are clear enough photos that show multiple sides of the structure, a 3D polygon shape can be created. The size and measurements of the building can be estimated from historic records and the digital twin scaled to the correct size. Then, once the basic building shape has been created, the same photos used to create the 3D polygon can be used to "texture" the sides so that it showcases what the building looked like in that moment. This method, while not entirely precise nor time efficient, allows for the creation of an environment that takes people back into a specific time and place. The ability to experience past landscapes in three dimensions, rather than through static photographs, creates opportunities to reacquaint with places as ancestors saw them and to understand better our obligations to those places today.
Applications & Use of Digital Twinning
Digital twins are novel tools for Tribes and cultural preservation because they allow for people to connect with and protect resources and heritage in new more holistic ways. For Tribes, these technologies, offer a way to safeguard knowledge and traditions tied to specific places, providing a digital record of cultural landscapes that can be shared across generations. A 3D model of site or artifact captures it at a particular moment in its lifecycle even as time, development, or natural disasters change its physical form.
Digital Twins can also be used to create dynamic, data-rich replicas of entire buildings, or even landscapes. These are not just static representations; they can let people interact with the environment virtually, analyze changes over time, and make informed decisions about protecting what matters most. For archaeological work, Digital Twins and 3D models allow for sites to be explored respectfully and without unnecessary damage, can be used for collaboration with partners, and for sharing findings in immersive, engaging ways.
A&R is using these new technologies to bring life to history, to honor the past while safeguarding and enriching future Practice, and to help keep tribal narratives alive and accessible for future generations.
Images
LiDAR Scan:Combining LiDAR scanning of 1880s mill foundations with ground-penetrating radar data and decade-old excavations to create a "view" potential features above and below surface.
3D Oregon City Models:Using historic photos to create textured 3D models of Oregon City. The block shapes are simple models based on the information obtained from georeferenced Sandborn insurance maps that indicate height and construction materials; brick (red) and wood (tan). The textured models were drawn in 3D polygon shapes for some of the more prominent buildings.
GPR Signal Output:GPR signal output. Yellow line shows feature consistent with a buried hard “surface” while the red arrow points to small feature such as a stone or pipe.
GPR:Ground Penetrating Radar (GPR), uses electromagnetic waves to detect reflection of the signal off of subsurface features, further enriches data, and archaeological reconstructions.
High resolution LiDAR scan of Mill Doorway at tumwata Village:. Image provided by our OSU Geomatics partners.
Photogrammetric model of 19th century brick wall at tumwata Village.