Tag Archives: geosemantics

Linked Data: From interoperable to interoperating

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

Piazza Mercato, Siena

Piazza Mercato, Siena

Videos of all the presentations in this CAA session, held in Siena 2015, which I blogged about earlier. Full credit and thanks due to Doug Rocks-Macqueen and his Recording Archaeology project for recording and making this and other sessions available (see also the session on ArchaeoFOSS and the keynotes). Thanks also to Leif Isaksen and Keith May for organising and chairing the session.

The session outline:

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 InstitutePhilipp Gerth, Sebastian Cuy (video)
  • Using CIDOC CRM for dynamically querying ArSol, a relational database, from the semantic webOlivier Marlet, Stéphane Curet, Xavier Rodier, Béatrice Bouchou-Markhoff (video)
  • How to move from Relational to Linked Open Data 5 Star – a numismatic exampleKarsten Tolle, David Wigg-Wolf (video)
  • The Labeling System: A bottom-up approach for enriched vocabularies in the humanitiesFlorian Thiery, Thomas Engel (video)
  • From interoperable to interoperating Geosemantic resourcesPaul J Cripps, Douglas Tudhope (video)

The playlist for the session:

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From interoperable to interoperating Geosemantic resources

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

Ospedale Psichiatrico - the conference venue, aka the Asylum...

Ospedale Psichiatrico – the conference venue, aka (rather appropriately, perhaps) the Asylum…


Following on from my earlier post on CAA2015, my presentation entitled From interoperable to interoperating Geosemantic resources is now available on YouTube thanks to Doug Rocks-Macqueen and his Recording Archaeology project. Indeed, there are a whole collection of presentations from the conference (and numerous others conferences) available, all thanks to Doug’s dedication; his work is a great asset to the community and the growing resource he is creating is of enormous benefit so all thanks due to Doug.

Anyway, back on topic.

There is a competition with a super special prize for the person who guesses correctly the number of times I say ‘um’ during the presentation; answers on a postcard please :-)

Whilst in Siena, as well as hearing all the fantastically interesting talks and networking over a beer or two, there was a little time for some sightseeing and photography:

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GSTAR @ Computer Applications in Archaeology (CAA) 2015

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

Conference

Conference

Following on from my presentation at CAA2014 in Paris, I was invited to submit a paper to a session at CAA2015 covering Linked Data (LD) and focussing on the difference between being theoretically interoperable and interoperating in practice.

Conference Session

The session abstract is as follows:

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.

We particularly invite papers that offer practical approaches and experience relating to:

  • Interface development and user support for ingestion, annotation and consumption
  • Management, publication and sustainability of Linked Data resources
  • Building cross and inter-domain Linked Data communities
  • Processes for establishing usage conventions of specific terms, vocabularies and ontologies
  • Alignment processes for overlapping vocabularies
  • Engage non-technical users with adopting semantic technologies
  • Licensing and acknowledgment in distributed systems (especially those across multiple legal jurisdictions)
  • Incorporation within other software paradigms: TEI, GIS, plain text, imaging software, VR, etc.
  • Access implications of integrating open and private content
  • Mapping the Field – what components are now properly in place? What remains to be done?

Papers should try to provide evidence of proposed approaches in use across multiple systems wherever possible. Purely theoretical papers and those dealing solely with a single data system are explicitly out of scope for this session.

Keywords: Linked Data, Semantic Web, Web Science

Conference Paper

The abstract for the paper is as follows:

From interoperable to interoperating Geosemantic resources; practical examples of producing and using Linked Geospatial Data

Paul Cripps, University of South Wales (paul.cripps@southwales.ac.uk);

Douglas Tudhope, University of South Wales (douglas.tudhope@southwales.ac.uk)

Keywords: Geospatial; Linked Data; ontology; CIDOC CRM; GeoSPARQL

The concept of using geospatial information within Semantic Web and Linked Data environments is not new. For example, geospatial information was very much at the heart of the CRMEH archaeological extension to the CIDOC CRM a decade ago (Cripps et al. 2004) although this was not implemented; a review of the situation regarding geosemantics in 2005 commented “the semantic web is not ready to provide the expressiveness in terms of rules and language for geospatial application” (O’Dea et al. 2005 p.73). It is only recently that Linked Geospatial Data has begun to become a reality through works such as GeoSPARQL (Perry & Herring 2012; Battle & Kolas 2012), a W3C/OGC standard, and the emerging CRMgeo standard (Doerr & Hiebel 2013). This paper presents some real world, practical examples of creating and working with archaeological geosemantic resources using currently available standards and Open Source tools.

The first example demonstrates a lightweight mapping between the CRMEH, CIDOC CRM and GeoSPARQL ontologies using data available from the Archaeology Data Service (ADS) digital archive and Linked Data repository. The second example demonstrates the use of Ordnance Survey (OS) Open Data within a Linked Data resource published via the ADS Linked Data repository. Both examples feature the use of Open Source tools including the STELLAR toolkit, Open Refine, Parliament, OS OpenSpace API and custom components developed and released under open license.

The first example will also be placed in the context of the GSTAR project which is using the approaches described to produce Linked Geospatial Data for research purposes from commonly used platforms for managing archaeological resources within the UK heritage sector. These include the Historic Buildings and Sites and Monuments Record  (HBSMR) software from exeGesIS, used by UK Historic Environment Records (HERs), and MODES, used by museums for managing museum collections. As such, the outputs from the GSTAR project have wider applicability in moving geosemantic information from interoperable to interoperating in the UK.

Battle, R. & Kolas, D., 2012. GeoSPARQL: Enabling a Geospatial Semantic Web. Semantic Web Journal, 0(0), pp.1–17.

Cripps, P. et al., 2004. Ontological Modelling of the work of the Centre for Archaeology, Heraklion. Available at: http://cidoc.ics.forth.gr/docs/Ontological_Modelling_Project_Report_ Sep2004.pdf.

Doerr, M. & Hiebel, G., 2013. CRMgeo : Linking the CIDOC CRM to GeoSPARQL through a Spatiotemporal Refinement, Heraklion.

O’Dea, D., Geoghegan, S. & Ekins, C., 2005. Dealing with geospatial information in the semantic web. In AOW ’05 Proceedings of the 2005 Australasian Ontology Workshop – Volume 58. pp. 69–73. Available at: http://dl.acm.org/citation.cfm?id=1151945 [Accessed April 13, 2013].

Perry, M. & Herring, J., 2012. OGC GeoSPARQL – A Geographic Query Language for RDF Data, Available at: http://www.opengis.net/doc/IS/geosparql/1.0.

GSTAR @ CAA: From interoperable to Interoperating

My work on the GSTAR project addresses exactly the issues raised in the session abstract through an investigation of the application of Linked Geospatial Data (LGD) and semantic web techniques for archaeological research purposes; This investigation builds on conceptual structures such as the CIDOC CRM, CRM-EH and GeoSPARQL, incorporating real world archaeological data from a range of sources through to providing working technology demonstrators. This was illustrated through the use of case studies based on my research and also through my work on projects such as the Colonisation of Britain project, undertaken for Wessex Archaeology, and the Later Silbury project, being undertaken for Historic England; the former resulted in a Linked Data resource now online at the Archaeology Data Service and the latter will do too upon completion.

Focussing on producing and then using LGD, my talk looked at the background to my research, the methods, techniques and tools used and some of the pitfalls and successes in creating interoperating LGD resources. I had hoped to be a bit further ahead and be able to demonstrate some map based querying and visualisation in action but at the time, these elements were not ready and interacting with a SPARQL endpoint is hardly the most audience grabbing activity! The research was also put into the context of the broader historic environment sector in England by showing how interoperating geosemantic resources could form the backbone of a digital ecosystem to support research, management and development control functions for a broad range of sectoral user groups.

Where next?

Since returning from Siena, work has proceeded apace to finalise the geosemantic resource ready for the next phase of activity; taking real world archaeological research questions and expressing these using GeoSPARQL queries to demonstrate the way in which such resources can be used for research purposes. Part of this involves engaging domain experts to see where and how their research interests can be elucidated through the applications of such approaches (more on this here).

Ultimately, the querying and results visualisation components will be housed in a web based interface, hiding the complexity of SPARQL endpoints, to demonstrate how geosemantic resources can underpin user focussed research tools such as Virtual Learning Environments. Whilst it would have been nice to present more of this at CAA2015, the plan is now to complete this phase over the summer ready for a fully fledged demonstration of the whole (completed and submitted) research project at CAA2016 in Oslo.

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Linking Geospatial Data 2014

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

LGD14 Barcamp, featuring open plan space and beanbags.

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.

Highlights

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!

Versioning

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.

Re-use

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).

Time

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.

Cool stuff!

Last but not least, there was a liberal spread of really cool stuff.

Strabon

Strabon had a few mentions, with a point made that the GeoKnow report 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.

Sextant

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.

RAGLD

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!

map4rdf

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.

Campus London

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…)

[flickr-gallery mode="photoset" photoset="72157642122872833"]

Summary

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.

Looking forward to LGD 15 :-)

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