3D Visualization for Archaeology and Open Educational Resources (OER)

By Chris Givan (JPPM Digital Education Coordinator) and Noah Boone (JPPM Digital Education Content Developer)

Photogrammetry is a technique for creating 3D models, which is increasingly common in cultural and research contexts. At Jefferson Patterson Park and Museum, we’ve been using photogrammetry to create models of archaeological sites and artifacts that may not be accessible to visitors or which may be of interest to folks for whom the park is inaccessible because of its location. Thanks to a project funded by an IMLS CARES Act Grant for Museums and Libraries, we’ve begun to provide photogrammetric models as Open Education Resources (OER) and are exploring how to replicate, at home or in the classroom, the experience of visiting archaeological sites or interacting with artifacts.

Photogrammetry software creates 3-dimensional data by analyzing photos taken at multiple angles around a subject. This can be done using a variety of programs, both proprietary (Agisoft Metashape, Reality Capture, etc) and free-and-open-source (Meshroom, MicMac, etc). This process requires a high degree of overlap between photos by moving the camera or subject in small increments, such as with small rotations on a turntable. The programs identify like points between these photographs and construct a 3-dimensional point cloud (below, left). This point cloud can then be further processed to create a 3-dimensional model that can be viewable and distributable for a variety of purposes (below, right).

Side-by-side comparison of a point-cloud, left, and a mesh, right, in Agisoft Metashape. The rectangles surrounding and overlapping the image are Agisoft’s estimation of where the camera was when a corresponding photograph was taken.

Photogrammetry is incredibly scalable and results are primarily dependent on camera equipment. This method can be used with drone photography for creating models of landscapes and buildings and macro-photography can even be used to create models of insects. Photogrammetry offers many exciting possibilities to look at things in a different light and look at things at angles or scales that would otherwise not be possible.

We’re using our models from photogrammetry in a number of ways. First, we will be making models available as resources for anyone with a use for them on JPPM’s SketchFab page. SketchFab is a website for hosting and sharing 3D models, which includes contributions from cultural institutions around the world. We particularly like SketchFab because museum accounts allow you to restrict downloads if dealing with artifacts or sites for which you have received permission to make the models viewable but not redistributable.

Below are two objects on SketchFab that we have scanned with photogrammetry. The model of the site known as Sukeek’s Cabin includes annotations, an additional benefit of using SketchFab that allows us to add educational content directly to models.

However, publishing on SketchFab does limit interactivity and we want to replicate some of the physicality of visiting sites or seeing artifacts up close. There are also practical limits to what can be included in annotations. To achieve more interactivity we’re using the service Genial.ly. SketchFab models can be embedded directly into Genial.ly “microsites” with rich media or additional interactivity. Below, we used photogrammetry to model an “alphabet plate” found at Sukeek’s Cabin. We’ve used Genial.ly to simulate another dimension of “handling” the object by encouraging viewers to reassemble 2D views of the fragments. Even though this additional interaction is 2-dimensional, it derives from photogrammetry of the plate. On an interesting note, we were able to do this by photographing the plate while it remained in its display at JPPM’s Visitor’s Center, and the interaction we’ve simulated is not actually possible in person given preservation needs.

To enable even more interactivity, we’re using Unity, a game engine for creating both 3D and 2D content. Unity is commonly used for indie games but its streamlined experience and support for computers, mobile devices, and web browsers makes it excellent for education–as does a large community of users and assets to help speed development. By shifting from SketchFab and Genial.ly, where we’re limited to either visualizing a model in 3-dimensions or simulating additional interactions with the model from 2-dimensional perspectives, Unity enables interaction with archaeological sites and artifacts from the first person perspective or with controllers that do a better job approximating the feel of an object.

In the video below, you can see a very early experience of “walking” around the Sukeek’s Cabin site here on park property. Despite the ghostly reconstruction (because parts of it are hypothetical or not known with confidence*), there is still a sense of hominess when inside and the stairs in the corner invite further exploration. In the distance, we have added a representation of the Peterson house. Newly emancipated, Sukeek and family were still living within sight of their former captor’s home. From the first person perspective, the house feels watchful–a feeling difficult to replicate in SketchFab or Genial.ly, missing from the site today, but true to the limits newly-freed families often found on their freedom.

A user explores the virtual environment around the Sukeek’s Cabin site. The photogrammetric model is visible on the ground as are interactive hotspots. A “ghost” of the home can be toggled on and off to get a sense of what it would have looked like.

We use these results in Open Education Resources (OER): free and openly-licensed resources that encourage reuse and remixing. (For more information, see this explainer from the University of Maryland or visit our Provider Set on OER Commons for examples.) For OER, photogrammetry offers a way to present lots of information with each resource. Photos and videos preserve how an artifact or archaeological site looks from a limited set of views, but digital models can preserve how a subject looks from any point of view, even those that may not be practically accessible. Where photogrammetry excels as an educational tool, though, is in approximating being able to tangibly interact with an artifact or site. While most interactions still rely on 2D screens, the opportunity to move and manipulate 3D models within those 2D interfaces helps replicate some of the sense of holding an object. As AR/VR and 3D printers improve, having a 3D model of an artifact or site will only improve in educational effectiveness.

*In addition to the current staff at JPPM, we are indebted to conversations with Kirsti Uunila and Ed Chaney for guidance on how the cabin would have looked.

Angling for Archeology

By Troy Nowak, Assistant State Underwater Archeologist, Maryland Historical Trust

“Catch anything?” is positively the most common question we are asked on the water.

“Perhaps?” is usually the correct answer, but not an answer anyone would expect or understand without explanation. There is never time to explain when piloting a skiff with a cable attached to a towfish astern, and crabpots, pilings, or other obstructions dead ahead. The answer is usually a simple “No,” hopefully not accompanied by a scramble to avoid collision.

Contrary to popular belief, we are never fishing and rarely searching for any particular archeological site or shipwreck. As part of the Maryland Historical Trust, Maryland’s State Historic Preservation Office, most of our time on the water is related to routine site inspections of areas where construction is planned, or surveys of areas where development is expected or erosion is accelerating.

John Fiveash and Brent ChippendaleMay 2017 Field Session (1)

John Fiveash and Brent Chippendale, volunteering with the Maryland Maritime Archeology Program as part of the 2017 Annual Field Session in Maryland Archeology.

Each year roughly 700 projects receiving state or federal licenses, permits, or funding find their way to our desks  for review in compliance with state and federal historic preservation laws. All involve activities with potential to impact submerged archeological historic properties and reviews of these projects can take from ten minutes to years of coordination with government agencies and project sponsors. Very few, about ten per year, require site inspections; even less result in recommendations to government agencies for archeological studies prior to construction or other ground disturbance. This process is the frontline against loss of submerged archeological sites and/or the information they can provide to development.

Most site inspections and surveys involve reconnaissance of a discrete area using a side scan sonar, a marine magnetometer, and an echo sounder. Side scan sonar allows us to record detailed images of submerged lands and objects regardless of water clarity and the marine magnetometer helps us find submerged and buried shipwrecks, wharves, or other structures or objects which cause localized distortions in the earth’s magnetic field. The echo sounder is largely used to make sure we don’t run the instruments or the skiff aground, but we can also use the data it collects to produce bathymetric maps which can allow comparisons between current bottom topography and historic charts and maps.

MAM Poster 2018web

This April, Maryland Archeology Month celebrated the 30th anniversary of the Maryland Maritime Archeology Program.

We rarely know if we “caught” anything significant without further work – typically including data processing and review, library and archival research, more survey, and occasionally diving.

Discovery of new sites not only happens during formal site inspections and surveys, but also, and quite often, during the trip home. We typically stow the magnetometer before we depart the area we are formally investigating. It is towed nearly 70 feet astern during operation creating a complication and potential hazard while cruising among other vessels. We often leave the sonar in the water, as it is usually either pole mounted or towed very close alongside, and adjust its range to cover a large area. Now painting in broad strokes, the sonar produces coarse-grained images unsuitable for a typical archeological survey, but good enough to detect large objects protruding from or sitting on the bottom.

Chester_River_Shipwreck

Wooden shipwreck recorded during the  final site visit of 2017.

The return trip usually is planned in advance to pass or quickly inspect areas where the remains of old boats and ships may be hiding, such as inlets where they were often discarded, and shoals where they often ran aground. This is usually the most relaxing and exciting part of the day. The work is done and we can use our knowledge, skill, and a bit of luck to “catch a big one.”

We are often fortunate enough to share the excitement of discovery with volunteers who assist at the helm or scrutinize incoming data for any indication of potential targets. When we get a “bite” we normally turn around and readjust the sonar to capture clear images such as the wooden shipwreck recorded by volunteer Bill Utley and me after the Maryland Maritime Archeology Program’s final site visit of 2017 (see shipwreck photo above). We look forward to returning to the site to learn more about its identity and significance and to more site visits, surveys, and discoveries like this one in 2018.

This post was adapted from Charting the Past:  30 Years of Exploring Maryland’s Submerged History, a booklet written in celebration of Maryland Archeology Month – April 2018.

The Maryland Maritime Archeology Program was established in 1988 in response to the Abandoned Shipwreck Act of 1987, which encourages states to study, protect, preserve, and manage shipwrecks embedded in or on state-controlled submerged lands, and in recognition of the importance of Maryland’s varied submerged cultural resources. The program inventories and manages these resources in collaboration with non-profit organizations and government agencies and shares information with the public through its education and outreach activities.

A Story Map of Women’s Suffrage in Maryland

By Kacy Rohn, Graduate Assistant Intern

As a graduate student in the University of Maryland’s School of Architecture, Planning, and Preservation, I had the opportunity to spend over a year interning with the Maryland Historical Trust and to work on a personally significant project – documenting the Maryland women’s suffrage movement.

HikersMDSoil

Image from the Baltimore Sun article “Maryland Is Invaded,” which detailed the Elkton, Maryland stop on the 1913 suffragists’ march from New York to Washington, DC. 

Generously funded by the Maryland Historical Trust’s Board of Trustees, this special project allowed me to develop a history of the statewide women’s suffrage movement and to identify significant suffrage sites, a timely endeavor as we approach the 100th anniversary of the passage of the 19th Amendment. Before this research, we had little idea that that Maryland’s suffragists (a term they preferred to the derogatory “suffragette”) had been so active or that they had worked in dozens of hitherto forgotten places around the state. In previous blog posts (which can be found here and here), I highlighted two of these stories and two historic sites with previously overlooked connections to the movement.

Now, I’m excited to share one of my final projects: a story map that presents a chronological overview of the important places and milestones of the Maryland suffrage movement. This story ranges from the earliest beginnings of the movement to the final passage of the 19th Amendment, showcasing Maryland women’s dedication to this long fight.

storymap

The women’s suffrage story map can be found on the Maryland Historical Trust website.

Though my internship has almost ended, I’m happy to see that this important project will continue. My research will be used by Maryland Historical Trust staff to nominate significant women’s suffrage sites to the National Register of Historic Places and will support other statewide efforts to preserve these sites and tell their stories.

A Summer with the Maryland Historical Trust – by Andrew Chase

The Maryland Historical Trust (MHT) enjoys hosting interns during the summer months. This year, we asked our interns to share their experiences with all of you! If you enjoy these blogs, please consider applying for an internship with MHT in 2017. 

Andrew Chase Visiting Crimea

The author on a site visit to Crimea, Baltimore City

I am a rising senior at Severna Park High School, and ever since I was young, I have had a profoundly great interest in history. I enjoy reading all sorts of histories, from political to economic to art and architecture. This summer, I spent two months completing an internship with the Maryland Historical Trust, Maryland’s State Historic Preservation Office. During my internship, I was able to get a closer look at Maryland’s history and see how we preserve our past. Continue reading

Maryland’s “Archeological Synthesis” Project

by Matthew D. McKnight, Research Archeologist, Maryland Historical Trust

Synthesis Project ScreenshotAre you a student, weekend researcher, or preservation professional with an interest in Maryland archeology? Are you a professional archeologist looking to conduct some background research on a specific artifact or site type? Have you been confounded in the past by lack of access to so much of the CRM “gray literature”? If so, the Maryland Historical Trust (MHT) has a new online resource that may be of interest to you. Continue reading