Yearly Archives: 2013

‘Between the Monuments’ at Avebury

Archaeogeomancy: Digital Heritage Specialists – archaeological geomatics – the majick of spatial data in archaeology – archaeological information systems for the digital age:

The dig in the West Kennet Avenue, August 2013

The dig in the West Kennet Avenue, August 2013

It’s been almost a decade since I was last digging at Avebury as part of the ‘Negotiating Avebury‘ project, so it was lovely to be invited along with my Avebury Archaeological and Historical Research Group (AAHRG) colleagues to visit the latest excavations at this amazing place, part of the current ‘Between the Monuments‘ project and following the team’s 2012 geophysical survey. This latest project features two of the site directors from the Negotiating Avebury Project, Dr Josh Pollard (University of Southampton) and Dr Mark Gillings (University of Leicester), joined this time by Dr Nick Snashall (National Trust) as co-director.

Looking back in time: Alexander Keiller's trench reopened

Looking back in time: Alexander Keiller’s trench reopened

This years dig has opened up two trenches in the area of the West Kennet Avenue where Alexander Keiller identified what he described as a settlement site. Indeed, one of the trenches has been opened up over one of Keiller’s trenches to see what remains and how he dug the site. The excavations are being blogged by the project team as work progresses.

I was amazed to see the deposits in this section of the Avenue. There is a virtually untouched soil going right down to the chalk, soil which looks to have never been ploughed or otherwise interfered with. There are also no major cut features one might expect to find in the chalk around Avebury and elsewhere. Instead, artefacts reside pretty much where they were deposited, helped into their final resting places by the usual range of natural processes such as worm action.

The deposits being excavated

The deposits being excavated

The nature of the deposits has led to the adoption of a slightly different excavation strategy. Single context style recording is not ideally suited so the site has been gridded and then excavated in spits down through the fairly homogeneous soil to the flinty layer and ultimately the chalk beneath. This will allow for fine horizontal and vertical spatial resolution in the excavation data, ideal for the intended GIS based analysis.

The nature of these deposits also raises questions about the often employed strategy common in commercial fieldwork where the ‘topsoil’ is machined off to reveal cut features in the chalk below; such an approach used here would have revealed nothing yet the site is demonstrably rich in information.

Spatial Data

The level; essential bit of archaeological survey kit

The level; essential bit of archaeological survey kit

With Mark Gillings involved, there was always going to be extensive (and exemplary) use of GIS. To support this, other data is being gathered including photogrammetric data captured using pole mounted cameras (courtesy of Adam Stanford and his amazing Aerial Cam landrover) and Unmanned Aerial Vehicles (UAVs). The data it is possible to capture using UAVs combined with photogrammetric techniques is highly detailed and most useful for archaeological investigations.

GSTAR

Another reason for my visit was to discuss possibilities relating to my GSTAR project and given that the Between the Monuments project is right in the middle of my study area and data from this site will be extensively digitised, the activities indexed by the HER and Oasis and artefacts lodged with the Wiltshire Heritage Museum, my intention is to look at using some of the data for one of my case studies. This case study will involve the application of Linked Data techniques to (spatial) data from excavations, heritage inventories and museums; more on this to follow later this year, but for now, many thanks to the project directors and the aforementioned organisations for their kind permission to reuse their data.

Trench 2 being excavated, with the megalithic avenue in the background and the Aerial Cam landrover

Trench 2 being excavated, with the megalithic avenue in the background and the Aerial Cam landrover

Photos, Panoramas and PhotoSynths

As usual, I took quite a few photos during my visit! A selection of the best are shown below, taken from my Flickr photoset. I also took the opportunity to create a panoramic image from atop the spoil heap and used all the images to create a PhotoSynth.

Flickr Gallery

[flickr-gallery mode=”photoset” photoset=”72157634971425709″]

Panorama

Photosynth

The post ‘Between the Monuments’ at Avebury appeared first on Archaeogeomancy: Digital Heritage Specialists.

Day of Archaeology, 2013

Day of Archaeology, 2013

Day of Archaeology, 2013

For the 3rd year running, I’ve blogged for the Day of Archaeology project, which is an amazing project, recording a snapshot each year of what archaeologists were doing on a particular day, this year on Friday 26th July 2013.

Some detailed modelling – archaeological excavation data

Pottery

Pottery

As part of my PhD research, the GSTAR project, I’ve been doing some more detailed work data modelling using the CRM-EH extensions to the CIDOC CRM, looking specifically at the concepts of ‘context’ aka ‘stratigraphic unit’ and how to model stratigraphy and context specialisms and relationships. Also the related processes by which objects become deposited in archaeological contexts and are subsequently found.

I will hopefully be publishing this work more fully in due course but for now here is a taster of some of the preliminary results.

This is very much open for discussion so any comments gratefully received.

Contexts and Stratigraphy: Positive and Negative Stratigraphic Units and related Events

The context is the fundamental unit of recording in many archaeological recording systems. We can think of archaeological contexts, representing discreet stratigraphic units, as being of two basic classes: Positive and Negative.

Positive Stratigraphic Units describe layers and deposits, ie the result of some material being deposited in a place whilst Negative Stratigraphic Units represent cuts, ie the result of some material being removed from a place.

Contexts and Specialisms

Contexts and Specialisms

Stratigraphy can be seen as the relative sequence of events resulting in these changes to archaeological deposits. A shortcut is used here for stratigraphically above/below (more accurately stratigraphically before/after) to provide a short chain representing this much longer sequence of events and event relationships.

Contexts and Stratigraphy

Contexts and Stratigraphy

Context Types and Relationships

All types of contexts have physical relationships with other contexts. The types of relationships depends on the type of context. Properties inherited from parent classes likewise.

Contexts can all be seen as subclasses of an overarching concept, the stratigraphic unit. These subclasses are generally represented in recording systems using different context sheets each holding common properties such as UIDs and classifications and also type specific properties such as physical relationships. Subtypes include masonry, timber and skeletons.

Context Relationships

Context Relationships

Finds deposition

Finds can be seen as ending up in archaeological deposits through some move event which could be a deliberate action or otherwise (eg an accidental loss). This forms one of the chain of events relating to objects beginning with their creation and initial use and/or display and eventually continuing beyond their rediscovery into the display and changes of custody in the world of museums and collections.

Finds Deposition

Finds Deposition

In addition to the act of discovery, however that may occur, a whole sequence of events then results in assignment of identifiers and classification using typologies.

Find discovery

Find discovery

 

Hestia 2 seminar – GSTAR presentation

I gave a talk on my PhD research (the GSTAR project) at the Hestia 2 event in Southampton last Thursday. Given I am still early on in the process, and having been asked to relate my work to the world of commercial archaeology, I decided to follow an overview of my research with some ideas for the future and how Linked Data approaches could be used to overhaul the (painful and convoluted) ways we manage heritage data in the UK.

The talk will soon be up on the project webpages and the slides are presented below via Slideshare. There are some great write ups of the day over on the Hestia webpages.

 

In the questions and discussion afterwards, a couple of topics that have presented before came up. Firstly, the idea that the CIDOC CRM and derivatives such as CRM EH are unnecessarily complicated. Secondly, the idea that this serves no useful purpose as very few people, if anyone at all, will be interested in using the richness contained therein.

Complicated and Complex

The first issue is one I have written up in my literature review but in one which requires further investigation. Ontologies such as the CIDOC CRM are indeed complicated and I have been quoted as describing working with them as ‘difficult’ (eg Isaksen, 2011). I do still think though that such approaches are unavoidable to adequately represent the complexity of heritage data. A major criticism of computational approaches in archaeology going back some decades was the idea that they are inherently reductionist; to fall back to overly simplistic data models has the potential to fall foul of the same problems inherent in what are now seen as legacy information systems, but in their day were equally as cutting edge as Linked Data approaches are today. There is a big difference between complex and complicated (see eg Kamensky, 2011) and the latter is sometimes essential to describe the former.

Complexity by versionz

Complexity by versionz

CIDOC CRM and extensions such as CRM EH can be described as complicated but working with them is quite straightforward once the class structure is understood. Especially the ability to create and use patterns, re-useable blocks which can easily be recycled. And the benefits of using such a rich model to describe complex scenarios far outweighs any disadvantages associated with complicated models and/or implementation difficulties. After all, the world both now and in the past is/was a complex place!

As an example, let’s look at the relationship between a find and the stratigraphic unit in which it was found. In CRM EH terms, we would start with a production event which would create the object and ultimately some kind of deposition event resulting in the find coming to rest in the location where it is ultimately found by an archaeologist through excavation or by a member of the public through a casual find or metal detecting or however.

A much simpler model would simply record a bunch of attributes against a find, a data-centric view of the world of data of the kind prevalent in relational systems modelled using eg entity-relationship type approaches. Taking classifications of finds in particular, this simple approach is problematic as without any explicit recording of the process of an archaeologist making assertions about a find in order to classify using some typology, the semantics of the archaeological process are lost and the real semantic benefits of Linked Data approaches are not realised. We end up with the same simplistic, ‘perfect’, idealised record of reality commonly found in many archaeological information systems.

Users…?

Audience? by orkomedix

Audience? by orkomedix

The notion that there is little audience for richer data models and resources has cropped up in numerous seminars, workshops and conference sessions I have attended and participated in. It is certainly true that many resources to date have not captured the richness of archaeological data and as such it is generally impossible to know why a find was classified in a particular way or which strands of evidence were used in the creation of the overall published narrative. But that is not to suggest that if our data models become more descriptive, this data will not be used. I have had equally as many if not more discussions of potential and desirable use cases for ways in which we can do more with such resources. Everything from better understandings of the archaeological process to tie research frameworks to fieldwork to synthesis in more meaningful ways through to managing change and the propagation of paradigm shifts such as revised typologies through to fieldwork datasets and heritage inventories. Knowing how we come to form then manage our shared knowledge base in the digital world is essential, given the highly theoretical, subjective, multi-vocal and often contradictory nature of archaeological discourse and scholarship.

Where next…?

Taking this to a logical progression would involve some implementation of working archaeological information systems incorporating some of these principals. So for example, moving to a situation where HERs become responsible solely for their own data, as does English Heritage, all of whom publish rich Linked Data which together forms a coherent, national record but without the current resource hungry problems relating to transfer and interchange of data and the all the redundancy, duplication and inconsistency that entails. For a fuller discussion of these themes, see Cripps, 2013.

So I think my research area has a good deal of promise and I hope to be able to demonstrate some practical outputs over the coming months. I will blog here as I go along. Do check back for updates.

References:

Cripps, Paul. 2013. “Places, People, Events and Stuff; Building Blocks for Archaeological Information Systems.” In Proceedings of the Computer Applications in Archaeology Conference, 2012.

Isaksen, Leif. 2011. “Archaeology and the Semantic Web.” PhD Thesis.

Kamensky, John. 2011. “Managing the complicated vs the Complex”. IBM Center for the Business of Government.

HESTIA2 – registration now open!

Archaeogeomancy: Digital Heritage Specialists – archaeological geomatics – the majick of spatial data in archaeology – archaeological information systems for the digital age:

Herodotus by Skara Kommun

Herodotus by Skara Kommun

Following on from the last post on this conference, the programme is now published and registration open.

I will be speaking about geosemantic technologies in archaeology and my GSTAR research, the abstract is as follows:

The semantics of heritage data is a growing area of interest with ontologies such as the CIDOC-CRM providing semantic frameworks and exemplary projects such as STAR and STELLAR demonstrating what can be done using semantic technologies applied to archaeological resources. In the world of the Semantic Web, advances regarding geosemantics have emerged to extend research more fully into the spatio-temporal domain, for example extending the SPARQL standard to produce GeoSPARQL. Importantly, the use of semantic technologies, particularly the structure of RDF, aligns with graph and network based approaches, providing a rich fusion of techniques for geospatial analysis of heritage data expressed in such a manner.

This paper will give an overview of the ongoing G-STAR research project (GeoSemantic Technologies for Archaeological Resources) with reference to broader sectoral links particularly to commercial archaeology.

Specifically, focus will be applied to approaches regarding the integration of spatial data into the heritage Global Graph and the relationship between Spatial Data Infrastructure (SDI) and Linked Data, moving beyond notions of ‘location’ as simple nodes, placenames and coordinates towards fuller support for complex geometries and advanced spatial reasoning.

Finally, the potential impacts of such research will be discussed with particular reference to the current practice of commercial archaeology, access to and publishing of (legacy, big) data, and leveraging network models to better understand and manage change within archaeological information systems.

See the conference website for full details and the calendar entry for when/where. Registration is free but tickets need to be booked in advance. Early registration is advised due to limited places.

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