Dreaming of total viewsheds on Caribbean beaches (new open access publication)

Today our new open access paper was published in Journal of Archaeological Science, introducing the concept of Visual Neighbourhood Configurations for total viewsheds. The method was conceived during a walk along the beach on the Caribbean island of Guadeloupe (I know what you’re thinking, my work is hard). From the beach it was really hard to spot boats at any great distance, let alone other islands. The beach I was walking on was very narrow and a plateau with steep edges rose up close-by. As I climbed higher and higher up the steep slopes I was offered great views of the surrounding sea and islands, “a great spot for the island’s former inhabitants to keep an eye on approaching enemies or on people using the beach” I thought. But it was also a very exposed spot, not many places to hide from approaching enemies. As I reached the plateau top the views changed dramatically. Walk just a few meters away from the plateau’s edges and you’re hidden from view to the people below and at sea. This place offered quite specific visual properties: past inhabitants had great vantage points nearby to see canoes and people approaching, whilst having their settlement hidden from view just meters away from the plateau edge. Could this explain the location of the few prehistoric settlements sitting right by the edge of the plateau?

DSC00095
Views from the plateau edge of La Désirade in Guadeloupe.

This is a phenomenon that concerns the visual properties of a small area rather than the properties of specific locations. When we explored the literature we could not find any methods for formally expressing such theories: all visibility studies in archaeology concern formal treatments of the visual properties of locations, with the properties of small areas being evaluated qualitatively. So there was some work for us to do: invent a new formal GIS method to test these archaeological theories. The first step was easy: create total viewsheds of landscapes.

Total viewsheds are awesome! They are representations of how visible each location in a landscape is from all other places. Archaeologists use them for exploring a wide range of theories about how the things past people could see affected how they behaved. But in the past it was basically impossible for me to play with total viewsheds because they involve many calculations that take a really long time. Until recently that is: present-day personal computers are so powerful that computation time is basically not prohibitive anymore. But there’s another problem: because of the limited use of total viewsheds in archaeology there are very few formal methods for me to play with. Developing new methods to work with total viewsheds is now more than ever worth our while.

Together with Mereke van Garderen and Mark Gillings, I developed the Visual Neighbourhood Configurations method to address the very limited practice of archaeologists formally expressing and testing their theories about how visibility patterns are structured. The concept recognises that such theories commonly concern not just the visibility of point locations but rather the structure of visibility in an area around focal locations. Visual Neighbourhood Configurations allow you to formally express your theory about how visibility is structured in a small area and compare it against the actual visibility as represented by total viewsheds to test the theory.

The below graphical abstract produced by Mereke van Garderen explains the method a bit better: a total viewshed is created, a visual neighbourhood configuration is formulated representing a visibility hypothesis, the fit between this configuration and each cell in the total viewshed is evaluated and represented as a new raster.

Want to know more? Read the full open access paper here.

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Graphical representation of the VNC method. Figure by Mereke van Garderen.

Highlights of the paper

    A new approach is presented for the formal representation and evaluation of complex visibility theories.
    Visual Neighbourhood Configurations (VNC) represent a theorized distribution of visual properties in a small area.
    Total viewsheds are input to the approach and are formally compared against the VNC representing the archaeological theory.
    A software tool has been developed to implement VNCs with a wide range of analytical techniques.
    VNCs represent a step towards more complex theoretical formal visibility studies.
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Evolution of cultural complexity CFP

I can strongly recommend submitting a proposal to this satellite session as well as attending the conference on complex systems. I went to the previous iteration and it was an inspiring event. Submit you abstract by 1 June 2018! Archaeological papers and network research will be very welcome.

We are pleased to announce a call for abstracts for our session on “Evolution of Cultural Complexity” at the annual “Conference on Complex System”. The Conference on Complex System will takes place this year in Thessaloniki, Greece, from the 23rd to the 27th of September. The satellites will take place between the 26th and 27th of September 2018.

Human sociocultural evolution has been documented throughout the history of humans and earlier hominins. This evolution manifests itself through development from tools as simple as a rock used to break nuts, to something as complex as a spaceship able to land man on other planets. Equally, we have witnessed evolution of human population towards complex multilevel social organisation.
Although cases of decrease and loss of this type of complexity have been reported, in global terms it tends to increase with time. Despite its significance, the conditions and the factors driving this increase are still poorly understood and subject to debate. Different hypothesis trying to explain the rise of sociocultural complexity in human societies have been proposed (demographic factor, cognitive component, historical contingency…) but so far no consensus has been reached.
Here we raise a number of questions:

1.
Can we better define sociocultural complexity and confirm its general tendency to increase over the course of human history?
2.
What are the main factors enabling an increase of cultural complexity?
3.
Are there reliable way to measure the complexity in material culture and social organisation constructs, that is?
4.
How can we quantify and compare the impact of different factors?
5.
What causes a loss of cultural complexity in a society? And how often these losses occurred in the past?

In this satellite meeting we want to bring together a community of researchers coming from different scientific domains and interested in different aspect of the evolution of social and cultural complexity. From archaeologists, to linguists, social scientists, historians and artificial intelligence specialists – the topic of sociocultural complexity transgresses traditional discipline boundaries. We want to establish and promote a constructive dialogue incorporating different perspectives: theoretical as well as empirical approaches, research based on historical and archaeological sources, as well as actual evidences and contemporary theories.

Submissions will be made by sending an abstract in PDF (maximum 250 words) via Easychair here: https://ccs18.bsc.es/call/ . The deadline for abstract submission is on the 1st of June 2018. The contributions to this satellite will be evaluated by the scientific committee through a peer review process that will evaluate the scientific quality and the relevance to the goal of this session. Notification of accepted abstracts will be communicated as soon as possible.

Please find more details on the following website: https://ccs18.bsc.es/
We strongly encourage you to participate

Spread the word

Simon Carrignon and Sergi Valverde

Visual connections between Caribbean islands (open access publication)

Today our paper on visual connections between Caribbean islands is published open access in print in Journal of Archaeological Method and Theory. It combines a wide range of different visibility analysis methods, both quantitative and qualitative, to explore the visual properties of Eastern Guadeloupe in the Caribbean. When does the island become visible when approaching it from the sea by Canoe? From what areas in the sea is it most visible? From what areas on land can canoes at sea be best observed? Are settlements located on good vantage points? Can other settlements be observed from these settlements?

We propose a hypothesis of the visual structuring of past island communities in the Lesser Antilles: short-distance visibility networks represent the structuring of navigation and communication within landmasses, whereas the landmasses themselves served as focal points for regional navigation and interaction. Can’t wait for people to engage critically with this hypothesis. Here is a figure by Mereke van Garderen and myself describing our hypothesis:

brughmans-etal-guadeloupe-fig11

This paper presents a study of the visual properties of natural and Amerindian cultural landscapes in late pre-colonial East-Guadeloupe and of how these visual properties affected social interactions. Through a review of descriptive and formal visibility studies in Caribbean archaeology, it reveals that the ability of visual properties to affect past human behaviour is frequently evoked but the more complex of these hypotheses are rarely studied formally. To explore such complex hypotheses, the current study applies a range of techniques: total viewsheds, cumulative viewsheds, visual neighbourhood configurations and visibility networks. Experiments were performed to explore the control of seascapes, the functioning of hypothetical smoke signalling networks, the correlation of these visual properties with stylistic similarities of material culture found at sites and the change of visual properties over time. The results of these experiments suggest that only few sites in Eastern Guadeloupe are located in areas that are particularly suitable to visually control possible sea routes for short- and long-distance exchange; that visual control over sea areas was not a factor of importance for the existence of micro-style areas; that during the early phase of the Late Ceramic Age networks per landmass are connected and dense and that they incorporate all sites, a structure that would allow hypothetical smoke signalling networks; and that the visual properties of locations of the late sites Morne Souffleur and Morne Cybèle-1 were not ideal for defensive purposes. These results led us to propose a multi-scalar hypothesis for how lines of sight between settlements in the Lesser Antilles could have structured past human behaviour: short-distance visibility networks represent the structuring of navigation and communication within landmasses, whereas the landmasses themselves served as focal points for regional navigation and interaction. We conclude by emphasising that since our archaeological theories about visual properties usually take a multi-scalar landscape perspective, there is a need for this perspective to be reflected in our formal visibility methods as is made possible by the methods used in this paper.

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