Yes, it’s that time of year again: Time for the annual Day of Archaeology. And once again, my day does not involve any temples in remote jungles, crystal skulls or raiding any tombs. Indeed, as has become the norm, it does not even involve any digging of holes, artefacts or suchlike.
Yep, archaeology involves a much broader range of activities than many folk believe, many of which are lab based and/or computer based with the result that some archaeologists (myself included) rarely get to see daylight let alone travel to distant far off lands in search of ancient peoples. And this is one reason why I love the Day of Archaeology so much as the range of posts each year covers just about every aspect of archaeology and cultural heritage and goes a long way towards showing what we, as professional archaeologists, really get up to, shattering stereotypes perpetuated by the likes of Indiana Jones and Lara Croft.
Anyway, here’s my post for this year which focusses on the usual range of geospatial and geosemantic stuff and not being chased by angry tribespeople or making dramatic and implausible escapes from imminent danger and almost certain death (although I did get a small electric shock off a laptop power supply this morning…)
Linked Data and Semantic Web based approaches to data management have now become commonplace in the field of heritage. So commonplace in fact, that despite frequent mention in digital literature, and a growing familiarity with concepts such as URIs and RDF across the domain, it is starting to see fall off in Computer Science conferences and journals as many of the purely technical issues are seen to be ‘solved’. So is the revolution over? We propose that until the benefits of Linked Data are seen in real interconnections between independent systems it will not properly have begun. This session will discuss the socio-technical challenges required to build a concrete Semantic Web in the heritage sector.
The videos for the accepted papers:
The Syrian Heritage Project in the IT infrastructure of the German Archaeological Institute – Philipp Gerth, Sebastian Cuy (video)
Using CIDOC CRM for dynamically querying ArSol, a relational database, from the semantic web – Olivier Marlet, Stéphane Curet, Xavier Rodier, Béatrice Bouchou-Markhoff (video)
How to move from Relational to Linked Open Data 5 Star – a numismatic example – Karsten Tolle, David Wigg-Wolf (video)
The Labeling System: A bottom-up approach for enriched vocabularies in the humanities – Florian Thiery, Thomas Engel (video)
From interoperable to interoperating Geosemantic resources – Paul J Cripps, Douglas Tudhope (video)
Postgraduate Researchers Presentation Day – 2nd prize for best oral presentation
I am very pleased to report that I won an award for my presentation on the GSTAR project at the Postgraduate Researchers Presentation Day, held on 15th May 2015 at the University of South Wales Postgraduate Research Centre, Trefforest Campus.
The award was for 2nd place best oral presentation. Very happymaking
It was also really good to have some positive feedback from professors and peers outside of my specific area of research. Next stop, thesis, viva and (hopefully) award of degree next year – fingers crossed!
LGD14 Barcamp, featuring open plan space and beanbags.
I was very pleased to attend this event co-organised by the World Wide Web Consortium (W3C) through the SmartOpenData project, the Open Geospatial Consortium (OGC), the UK Government (data.gov.uk), the Ordnance Survey (OS) and Google. Hosted by Google Campus London, the two day event comprised presentations, lightening talks and a barcamp, all focussing on the use of geospatial data within the world of Linked Data. It was refreshing to be amongst researchers, users, developers and commercial folk all working in this area; I for one picked up some good ideas to help with my research project and hopefully my contributions were of use.
It was certainly good to bring together the camps working in this area: the geospatial technologists on the one side and the web folks on the other (And people like me who have one foot in each camp, as well as limbs in other domains, my primary domain being digital cultural heritage of course). To make this stuff work it’s going to take both groups working together through their respective consortia, the W3C and OGC.
I noted a number of specific highlights that really inspired and gave me food for thought. Some reinforced my own perceptions and others gave me some new ideas for application to my project. The extensive use of IRC and Twitter combined with fast internet access throughout the event made it possible to discuss and find out more whilst talks were ongoing. The format lent itself to interaction and I was impressed by the amount of progress made in such a short space of time, with new working groups forming and ideas for revisions to standards such as GeoSPARQL forthcoming.
Some of my favourite bits:
Ontologies and Linked Data
The discussion of the relationship of ontologies to Linked Data resources was informative. Whilst there is tendency in the world of the web to target the low hanging fruit, publish data and sort out issues later, it is my opinion that there needs to be robust semantics within our Linked Data resources. Otherwise we have a web of mess rather than semantically interoperable data. I noted a couple of points made by Tim Duffy (British Geological Survey) that resonated here:
Kerry Taylor (Commonwealth Scientific and Industrial Research Organisation) gave some examples of where ontological development can support but also restrict aims, showing how things can go wrong when trying to implement the various standards out there. This is an important point; ontologies need to be simple enough to work with but also suit the domain and applications.
GeoSPARQL and geometries
It was interesting to note that the use of Well Known Text (WKT) within GeoSPARQL can be problematic; hearing Lars G. Svensson (Deutsche Nationalbibliothek) talk about their experiences was reassuring given my experiences over the past few months!
Two crucial issues were raised by Raphaël Troncy (Eurecom) relating firstly to the use of coordinate systems and secondly to the way in which geometries are represented. I have often found the way in which geospatial data is used on the web to be problematic, with web developers focussing solely on location with only minimal respect for Coordinate Reference Systems (CRS), Spatial Reference System (SRS) or Spatial Reference Identifiers (SRID). In many cases, this is an acceptable way of working (if you just want features on maps in roughly the right place) but lack of clarity regarding spatial frameworks is problematic for any more detailed use of geospatial data. Being explicit about coordinate systems is essential for transforming between different coordinate systems and also takes into account factors such as tectonic plate movement. Put simply, assuming WGS84 is the only way to reference coordinates is a gross oversimplification.
Secondly, he went on to talk about the implementation of this within GeoSPARQL. The standard does support CRS (a good start) but the implementation is a little complex in my view. He suggested making CRS definitions simply part of the semantic model rather than being fudged into a geometry node as they currently are; a geometry node currently comprises up to three parts, the first being an (optional) SRID, the second being the geometry itself and the third being a literal describing the format of the geometry (eg a WKT or GML literal). It was suggested that these could better be stored as individual assertions relating to a geometry object and this was well received and may well appear in the next version of the standard: hurrah!
great idea from @rtroncy – represent the #CRS / #SRID as an explicit triple rather than as part of the geometry node – YES!!! #lgd14
A thorny issue if ever there was one. With heritage data in particular, it is important to know provenance of vocabularies. This topic came up a couple of times and it was pleasing to hear that a lightweight solution exists (current and then historical, versioned namespaces; bit clunky but doable) and versioning can be more fully supported using ontologies designed for the purpose.
A key question with Linked Data is how do you know who is using your data? Does this matter? Arguably not, but as with anything, proper citation and accreditation is useful, polite and can be used to demonstrate impact (a good thing when looking for funding). Turns out that Adam Leadbetter (British Oceanographic Data Centre) and Dicky Allison (Woods Hole Oceanographic Institution) have both been using the Heritage Data vocabularies I blogged about previously, which is great stuff but this only came to light through seeing the inclusion of English Heritage as a provider on one of their slides!
Precision & Accuracy
Important concepts for heritage data are precision and accuracy. When working with historic maps in particular it is important to be able to record tolerances against which data has been captured. As with coordinate systems, this is an area often ignored in the world of Linked Data with coordinates expressed to spurious levels of precision (ten decimal places is a *seriously* precise measurement!) with no metadata to describe overall accuracy. Coming from a geospatial background where these are core items of metadata, the lack of proper support for this within current Linked Data standards is problematic. It took a speaker working with heritage data to make this point; nice one Rob Warren (Big Data Institute, Dalhousie University).
There was talk of temporal aspects to data, most spatial data have some kind of temporal component to it. Interestingly, the data I work with is placed in archaeological time and rarely do we have any absolute temporal data; chronologies are typically relative and imprecise with occasional pegs to actual temporal classes generally used in Linked Data (timestamps, dates, etc). I think this makes for an interesting area to try out ideas and the way this is represented in cultural heritage ontologies such as the CIDOC CRM, whilst being a bit different to the norm, actually encapsulates some very powerful constructs for working with spatio-temporal data.
Last but not least, there was a liberal spread of really cool stuff.
Strabon had a few mentions, with a point made that the GeoKnowreport on platforms had evaluated an old version and actually Strabon is now a very capable and scalable system. Being a semantic spatio-temporal system built from the ground up rather than than adding semantic, spatial and temporal functionality to an existing system sounds promising. I will certainly be reviewing it in more detail as a result.
Also, building on the Strabon system comes Sextant. This application is described as:
Sextant is a web-based system for the visualization and exploration of time-evolving linked geospatial data and the creation, sharing, and collaborative editing of `temporally-enriched’ thematic maps which are produced by combining different sources of such data and other geospatial information available in standard OGC file formats (e.g., KML).
This looks like a very interesting platform for mapping geosemantic data, one which I will definitely be investigating further.
An absolutely brilliant piece of work was presented by John Goodwin (Ordnance Survey) called entitled Rapid Assembly of Geo-centred Linked Data applications (RAGLD). A collaboration between the University of Southampton, Ordnance Survey and Seme4, this project provides a neat suite of developer tools (currently in beta) for working with Linked Geospatial Data. Massive +1 from me!
Another really interesting platform is map4rdf. This is described as:
map4rdf is a mapping and faceted browsing tool for exploring and visualizing RDF datasets enhanced with geometrical Information. map4rdf is an open source software. Just configure it to use your SPARQL endpoint and provide your users with a nice map-based visualization of your data.
Again, this is one I will be investigating further for my GSTAR project.
Is just cool. Enough said. Love their displays of historical computer gear and of course the open plan, bean bag filled working space. Really tempted to join up and hang out there more (if only the trains to London didn’t require a mortgage…)
A brilliant event, well organised and some amazing ideas and discussion. Not only that, but an excellent forum for meeting people working in the same subject area; my Twitter peeps grew considerably as a result and I’ve added lots of new folks to my LinkedGeoData list.
Big thanks of course to John Goodwin and Phil Archer for leading on the organisation front.
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
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 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.
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.
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
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.