GIS for Archaeology and CRM

“EarthWorks“, a travelling exhibit that opened on June 20th at the Cincinnati Museum Center, Ohio, is a multimedia spectacle with an amazing centerpiece consisting of an immersing 3D journey through reconstructions of Native American “mound builder” villages and earthworks.

Technology of “EarthWorks” Exhibit
Beginning in the late 1990’s, John Hancock, University of Cincinnati professor of architecture and team member in the Center for the Electronic Reconstruction of Historical and Archaeological Sites (CERHAS) at the university, began to build interactive user environments set within reconstructed heritage sites. Simulations such as this, although popular at the time, were too large and unstructured, lacking feedback for the user and usually had over complex controls.

Noting the lack of usability, Dr. Hancock and the CERHAS team developed and new form of interaction consisting of an exploratory virtual reality framework, mixed multi-media presentations, and defined documentary narratives. Together, the mixture of media and documentation within an exploratory context create a “chose your own adventure” like experience where you learn and interact along a virtual path. The narrative and media experience has such a great depth that it is highlyT unlikely that a user could duplicate their previous path.

The end result of this “EarthWorks“ project is a 500 square foot traveling exhibit focused on the virtual reconstructions, but also including a very large map of the Ohio Valley area, a cross-cultural comparative time line, 3-D models of a series of earth works, and additional photos and narratives.
links to archaeology

A bit about the ancient Ohio Valley earth works

From around 600 BC to 1200 AD, the areas around Ohio, Kentucky, Indiana and West Virginia were home to populations of Native Americans that archaeologists refer to as Adena, Hopewell, and Fort Ancient. These groups, beginning with the Adena, built increasingly complexity earth mounds that began as circles and cones, evolved to complex geometric shapes, and ended with great animal effigies. The arrangement of geometric shapes and animal effigies, some reaching 15 feet high and thousands of feet in length, constitute some of the earliest ancient observatories in the world.

Although many have been lost to time, some earth works have remained intact. One of the most striking examples in Serpent Mound in Adams County, Ohio. This mound is a 1,300 foot long, three feet high effigy of a snake. Another extant mound structure is the great Fort Ancient hill top enclosure in Fort Ancient, Ohio. Enclosing 100 acres, the hill top earthworks is formed by a 3 mile long wall enclosure that is as high as 23 feet in some sections. Both examples are central to the EarthWorks exhibit.

The fact that Dr. Hancock, who taught ancient architecture for 15 years, was unaware of the massive 2000 year old earthworks practically under his feet, underscores the point that most people do not know that natives of North America created large earthworks. Although the construction technology of these celestial observatories and religious sites is primitive, as compared to the Inca and Egyptians, the cultural structure and depth of knowledge that is needed to create them is just as advanced.

An EarthWorks project and resources CD Avaliable from CERHAS for $25.
The EarthWorks tour schedule includes the following date:

• Cincinnati Museum Center, with opening on June 20, 2006
• Ohio Historical Center, Columbus, where the exhibit will open Sept. 30, 2006
• Cleveland Museum of Natural History in 2007
• The Field Museum, Chicago, (as part of a permanent exhibit) in spring 2007
• Sunwatch Indian Village/Archaeological Park, Dayton, Ohio, set to open May 26, 2007

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As I mentioned last week, the current Spring 2006 issue of ESRI ArcNews, has a series of articles on the use of GIS in Archaeology and more specifically Cultural Resource Management. This post is a short synopsis of one particular article on the use of GIS for the creation of a state wide archaeological sessitiity model for Vermont.

Overview of VTASM (link to article)
The Vermont Archaeological Sensitivity Model (VTASM) is a joint project between the Vermont Division of Historic Preservation (DHP) and the Vermont Agency of Transportation (VTrans), created with the guidance of the University of Maine at Farmington Archaeology Reaserch Center (UMFARC), the University of Vermont Consulting Archaeology Program (UVMCAP), and ESRI business partner, Earth Analytic Inc.

In general, this model is an inductive environmentally based model using ESRI ArcGIS ModelBuilder, Spatial Analyst, and 3D analyst to produce a state wide, 10 m resultion coverage, demonstrating archaeological sensitivity. The creation of a state wide sensitvitiy model, such as this, follows a trend set by other states, paticulary, Minnisota and North Carolina.

Used during a projects planning phase, a model such as the VTASM, allows archaeologist and transprtation planners the ability to query the archaeological impact of a project or variations of a particualr design. By gauging the possible extent of impact on archaeoligcal resources, the planning agency can create a much more efficient budget or stear clear of potential large archaeological investigations. While this is the underlying theory behind wide scale models, as the stakeholders of the VTASM has recognized, sensitivity models are only abostractions of recorded archaeoligcal knowledge mated with modern environmnetal conditions to create a “best guess” of where sites may be located. Even though the VTASM produces high scores for predicability, it is a guide and not a subsititute for archaeological field survey.

As mentioned, the VTASM is created through the weighted sum of correlative distance buffers of a selection of environmental features. Through years of survey and knowledge, archaeoligsts build up mental models of archaeological site location. These models often include, distance from water, slope angle, proximity to wetland. The VTASM, and similar models, quantify site location knowledge, through a rule base or correlation statistics, into raster layers which when overlain are summed to achieve the overall sensitivity for each cell.

In the VTASM, the environemtnal atributes are computed into 11 environmental compnent models (ECMs). Six of the ECMs are computed for water related features such as streams, confulences, and wetlands. The remaining five ECMs are realted to lakes, floodplains, soils, slope, and glacial features. Each ECM is a sesitivity raster which assigns a weighted value based on the proximity to one or more environemtal attributes. For example, through correlation or survey findings, the project team knows that archaeoligical sites are more likely within a range of 100m to 200m of a stream confluence. Using this, the ECM is weigthed higher in the 100m to 200m buffer distance.

The final VTASM model, which is computed on the fly for the area under investigation, is the weighted sum total of all overlapping ECMs. The weights assigned to each ECM are adjustable and can be fine tuned based on the environmental character of the region under investigation.

A Bit about Sesitivtiy Modeling

An archaeological sensitivity model, often referred to as predictive models, is simply an expression of a single or multiple attributes that demonstrates the sensitivity (probablitity or possibility) that a specifiic location on earth has been utilized by people in the past. “In the past” may refer to 100 years ago or 100,000 years ago. In Vermont and the Eastern US, models such as this generally related to ~12,000 to ~500 years ago.

Sesitivty models, s described above, are often cell based raster grids created through map algebra of one form or another. The unit of analysis for raster based sensitivity models can be of any size, but generally, in accordance with the use of USGS Digital Elevation Models (DEM), a 10 meter or 30 meter resolution is used. In the Vermont example, the overal model is at a 10m resolution, which uses a combination of 30m and 8m Lidar DEMs.

Although the general technological underpinnings of sesntivity models are often the same, the theoretical guidlines can be substantially different. The two main catagories that archaeoligical sensitivty models are put into consist of Inductive or Deductive. The claimed difference between the two is “explanitory power”. Abstractly, an Inductive model (aka emprical model, correlative model) correlates known site location to environmental features to create a “fingerprint” for where sites most often are found. This type of model does not attempt to exmplain why sites are located where they are. On the other hand, Deductive sensitivity models attempt to use what we know of past human behaviors to create a explantion of why sites may be found in certain places. Explination of archaeoligcal phenomina is the primary goal of the deductive model.

Here is a great PDF [1.25 megs] that explains various types of sesitivity models.

The inductive/deductive divsion, in my mind, is akin to a major politcal debate drawn down party lines where each side is arguing the same darn thing but spun in thier favor. For your sake, my thoughts on the difference between the two will be save for a seperate post, but what is important to mention is that within Cultural Resource Managment (CRM) in America, the inductive model is most frequently used. This model has a solid history of test and application. The technical methodology is documented, repeatable, and testable. And most inportantly, it is the most cost effective way to consult the client on where it will cost them lots of money to put a road.

I’m sure some of these reasons are why the Vermont DHR and VTrans decided to build the VTASM the way they did. The model they created is flexible and testable. As archaeoligsts learn more and continue to survey the landscape, the model can be added too and tweak to ablige. The use of VTASM as a common model helps foster communication and trust between the DHR and the Transportation Athourity leading to the likleyhood of better archaeoligcal resource protection. As with Minnesota, North Carolina, and now Vermont, more states are bound to follow this example.

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Dave at GisPilot.com emailed me a link to a cool use of the MapBender WMS to display the location of Pre-Columbian Mayan archaeological sites across Mesoamerica (wikipedia link for Mayan civilization). In order to load the numerous Mayan sites, a click of the zoom-in tool is needed. I was quite surprised by the number of sites documented in this project.

The Mapbender suite used in the creation of the Mayan archaeology site is a free, OGC compliant, Open Source Geospatial Foundation project that implements the management of spatial data services using PHP, Javascript, and XML. Though, even users with limited knowledge of these languages can produce mapping services relatively quickly. As expressed by the Mayan map creator:

“…mapping archaeological sites of the pre-Columbian Maya culture in Middle America was the work of only a few days by a not very experienced user. It demonstrates the benefits of such GIS applications to the public services and helps present day archaeologist to analyze their data under new points of view and new questions…” (German translation probably source of sentence errors)

Also discussed by the WMS applications author and elsewhere, the public mapping of archaeology sites is usually restricted to sites that have above ground components, such as pyramids, temples, or earthworks. In the field of archaeology there is a culture, both institutionalized and mandated by law, that archaeology site locations are to be kept secret. It is a general fear of looting, pot hunting, medal detectorists, and vandalism that keep this notion alive. In situations such as the Mayan site WMS, accuracy and findability of sites can be controlled by available base map resolution and introduced error. Although, with some Mayan sites, it’s not to hard to find the 200ft tall temple.

The introduction of error and low resolution may hamper some research agendas, but have an idea that combining an accurate environmental database with a slightly inaccurate map may be a way around this. Much of the site specific data that researchers would be interested in consists of elevation, slope, soil type, bedrock geology, as well as the types and dates of artifacts. The data served by the WMS application can have very accurate site specific environmental data, derived from the sites true location, while the map of the site is squwed to a certain extent. I know this spatial encryption is far from fool proof, but it might give enough uncertinaty to site location to both satisfy the state laws on displaying site location and dissuade a would be vandal.

Okay, now that we have figured it out, let the Archaeo-Mashups roll!!!

Background on Mayan Civilization

The Pre-Columbian Mayan civilization flourished in Mesoamerica (central Mexico south to Costa Rica) from ~1000 BC to just before the the arrival of the Spanish in 1519. Across this span of time, the pre-Columbian Mayan civilization grew from little known roots, flourished into an incredible complex society, and declined in prominence with wide spread warfare. The Mayan are known for monumental architecture, high style art work, writing, and math to name a few. After the colonization of their homeland by the Spanish in the 16th century, the remaining Mayan people integrated into society and continued with their customs. Today, there are still many Mayan people in the area that the pre-Columbian civilization once occupied.

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Since the discovery of the first Neanderthal (wikipedia) remains in Düsseldorf, Germany, 1856, Homo neanderthalensis has been one of the most studied human species. From findings across Europe and Western Asia, dating from ~230,000 to ~29,000 years ago, a sizable and diverse collections of Neaderthal remains and artifacts have been collected.

It is the goal of The Neanderthal Tools (TNT), in collaboration with The Neanderthal Studies Professional Online Service (NESPOS), to complete “Europe’s singular cultural heritage” for Neandethal remains, fossils, and ecofacts in a web based repository. This repository will offers tools for the examination and exploration of a complete archaeological workflow from site topography down to the 3D models and documentation of individual fossil finds.

“The TNT applications take advantage of state-of-the-art technology to provide a virtual public collection of fossils and artefacts which is open to the scientific community. The Neanderthal Tools enable scientifically valid research on virtual primary sources for the first time.”

The three tools used by the TNT to achieve this goal are the wiki based collaborative platform of NESPOS, the Visual Simulation and Collaborative Rendering Engine (VISICORE) Suite of GIS, annotation, and visualization software, and the National Geographic ArchChannel (NatAC), a public oriented web portal sponsored by National Geographic.

VISICORE: 3D GIS Tools for Archaeology

The VISICORE suite looks like an amazing set of tools. Within the suite there is The Artefact Exploration and Collaboration Rendering Engine (ArteCore) and The Geofact Mapping and Rendering Engine (GeoCore).

ArteCore is an artifact visualization and analysis program that allows users to explore Neaderthal fossils and finds. As part of the project, the TNT team and collaborators have CT scanned, created 3D models (in stl format), and 6 sided images which can all be accessed with ArteCore. Using the tools of ArteCore, these finds can be measured and analysis (using volume, angles, distance, area, etc…) as if they were the original specimens. ArteCore also has the capabilities to bring in multiple models in stl or X3D format, as well as, do CT to STL polyginization.

Further the GeoCORE Suite extends the visualization and analysis to the site level. Built off 3D Geo’s LandXPlorer, GeoCore allows for the visualization and integration of 3D GeoData in a number of popular formats. GeoCore also allows for the implementation of video, audio, and 2D media. Thematic mapping, virtual rendering, TINs, Bockstein Cross Sections, and map overlays are some of the functions supported by GeoCore.

The VISICORE suite, in total, is a multi-scalar analysis and visualization package that fits the mold of a archaeology/paleoarchaeology specific 3D GIS package. These tools are created by the TNT team and only avaliable through the NESPOS service.

NESPOS is the portal from which the vast amount of Neanderthal related data and imagery is served. In order to access this store house, you must be a member of the society. A Student membership is 30 Euro ($38.37) and a Single membership is 100 euro ($127.90). A membership includes a years access to the repository, scientific paper, VISICORE suite, and CT scans and STL 3D models of fossil finds. (I am not a member, nor affiliated with NESPOS. This is only for your information)

As an archaeologist, I have only a passive fascination with Neanderthal paleoarchaeology, but I am definitely tempted to join NESPOS just to play with the VISICORE suite of 3D GIS tool. Having scouted around a bit, I get the sense that the NESPOS is considering a limited form of public access to the Neaderthal database. As far as I am aware of, this project is the most advanced media and software enabled colobrative site going. As described by the site, a membership in NESPOS includes your own non-public data store. I assume this enables the user to store queries, notes, and favorte models and sites. Perhaps tagging is also invloved in this data store. As a comparitive project, although not Neaderthal specific, check out my post on the collabrotive archaeology data project at Open Context.

*Images are property of TNT and NESPOS

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