Saving Treasures of the World Heritage at the Digital Archive DANS

Hella Hollander

Data Archiving and Networked Services (DANS), Anna van Saksenlaan 51, 2593 HW Den Haag, Netherlands.

Cite this as: Hollander, H. 2017 Saving Treasures of the World Heritage at the Digital Archive DANS, Internet Archaeology 43.

Why is it necessary to store archaeological data in a digital archive that follows policies, protocols and strict procedures? Why not simply put your files in Dropbox? This article will explain in detail the benefits of the existence and use of certified digital repositories saving the cultural wealth of archaeological research data, the impact of national regulations for conducting archaeology, the trend of clustering European infrastructures with a focus on cultural heritage and, finally, give some future recommendations for shared European archaeological polices to ensure good quality of metadata, data and repositories.

This extended abstract is also available in hard copy in K. May (ed) 2017 Digital Archaeological Heritage, EAC Occasional Paper No.12, Archaeolingua, Budapest.

Hidden treasures in the sea of data

Why is it necessary to store archaeological data in a digital archive that follows policies, protocols and strict procedures? Why not simply put your files in Dropbox? This article will explain in detail the benefits of the existence and use of certified digital repositories, the impact of national regulations for conducting archaeology, the trend of clustering European infrastructures with a focus on cultural heritage and finally, give some future recommendations for shared European archaeological polices to ensure good quality of metadata, data and repositories.

Certification for digital data archives

DANS (Data Archiving and Networked Services, The Hague, The Netherlands,, the Dutch national digital research archive, is an institute of the Royal Netherlands Academy of Arts and Sciences (KNAW) and the Netherlands Organisation for Scientific Research (NWO). Collaboration between the Dutch Cultural Heritage Agency (RCE) and DANS makes it possible to ensure sustainable archiving and unlocking of digital documentation of cultural heritage in a central national repository.

There is a great need to store archaeological data in a sustainable manner. What happens if an organisation loses their data, for example because the lifespan of the discs on which the excavation archives are stored is shorter than expected, or software ageing causes a system failure? An excavation cannot be done twice; the work to scan possible remaining analogue material such as photographs is enormous and probably the associated documentation (metadata) would be missing. Without information describing the image, the scientific value of it would be lost. Reorganisations within the archaeological sector are common and sometimes the data are forgotten as the result of changes in personnel. Data is not well described and cannot be understood anymore. A solid backup strategy is needed to protect this unique type of data presenting the world heritage.

In the Netherlands, DANS acts as a trusted repository to curate the archaeological data. The data remain accessible and usable in the long term at the national e-depot for Dutch Archaeology located at DANS. A wealth of archaeological excavation and exploration data such as maps, field drawings, photographs, tables and publications are digitally accessible via EASY, the online archiving service ( The description and data relating to thousands of archaeological research collections can be downloaded. The data are stored according to protocols and standards that make them easy to recover and share.

What actually is a trusted repository? DANS has the remit to provide reliable long-term access and therefore operates according to the OAIS (Open Archival Information System) model for digital archives. DANS holds the Data Seal of Approval (DSA), the internationally recognised quality mark for trusted digital repositories. In 2016 DANS extended this basic DSA certification with the DIN 31644 certification, which is based on an externally reviewed self-audit. The highest standard is the ISO 16363 and DANS has recently completed the test application for this certification. As a Regular Member of the International Council for Science – World Data System (ICSU-WDS), DANS is certified according to international standards and seen as a trustworthy party in terms of authenticity, integrity, confidentiality and availability of data and services. The preservation policy of DANS outlines the principles of sustainable archiving. Constant monitoring and biannual revision of this preservation policy improves the quality of the archive as the impact of threats and risks are understood. National and international agreed standards for digital preservation are followed and audits take place on a regular basis.

Revision of national regulations for conducting archaeology

In July 2016 the new Dutch Cultural Heritage Law replaced the old system of excavation permits with a new system based on certification. Archaeologists deposit their completed research results at DANS to boost their work’s visibility and accessibility. A national protocol was introduced and used to describe, exchange and deposit data. Agreements to this end have been laid down in the quality standard for Dutch archaeology called 'KNA’. Over the last two years the Dutch archaeological community worked together to update this standard, and included digital methodologies and the statement that the archaeological data should be archived at a trusted repository which is certified (minimally DSA) according to the European Framework for Audit and Certification of Trusted Digital Repositories.

After submitting the data at DANS (deposit instructions for archaeological data | January 2013:, a data manager will process the data according to an established protocol. The metadata (extended Dublin Core) and the readability of the files will be checked. If this has not yet been done, the data archivist will also convert the files into a durable digital file format. This preservation format is often a simple text file format that is also used for exchange purposes (csv, dxf, mif/mid). The files will be archived both in the original (native) format and in the preservation format. In the presentation of the research project, the files will only be displayed in the preservation format. This will enable as many researchers as possible to reuse these data while using their own software.

For each data type, a brief overview is given of the preferred format chosen, the use of the data, and any conversion possibilities. It is a dynamic document, and a working group within DANS is responsible for monitoring file formats and updating the recommendations based on new developments. It is far from being the only list of recommendations regarding file formats in the world. There are numerous other sources and wikis about formats and risks. DANS has evaluated several existing documents based on their experiences with the file formats encountered (;;; DANS encourages researchers to let their deposited data enter the public domain using the Creative Commons Zero (CCO) licence, a common international standard.

A majority of the data is in the public domain; 80% is open access. The remaining 20% is restricted to professional archaeologists or is available on request. After 10 years of archiving data digitally, Dutch archaeologists are used to sharing their data and show a growing trust in other people who want to use their data.

DANS is interested in the opinion of users who have downloaded datasets from EASY. They are asked for feedback as this can be helpful for other users and a general impression of the quality of the datasets can be offered.

Clustering of European infrastructures

To integrate archaeological data at a European level the ARIADNEInfrastructure was set up in 2013. Now, in 2016, a portal exists that has search and browse functionality, thus allowing researchers or the broader public with an interest in archaeology to cross search through time and space. Thesauri are helping to link related terms in different languages. The data of partners from 16 countries have commonalities that allowed integration.

Table 1 gives an overview of the current contents of the Catalogue. All descriptions provided by the ARIADNE partners could be mapped to the ACDM and therefore inserted into the Catalogue. The numbers are already significant, covering a large percentage of the data made available by the ARIADNE partners. Further additions are expected before the end of the project. Above all, it is expected that opening the Catalogue to the whole archaeological community will bring other descriptions, further enlarging the ARIADNE information space’ (taken from Binding et al. forthcoming ARIADNE: a research infrastructure for archaeology, Journal on Computing and Cultural Heritage).

To increase data visibility to a broad public and to integrate data on a European level, DANS ensures that archaeological and dendrochronological data are included in portals like Europeana and ARIADNE. Tree-ring data, coming from dendrochronological research done at archaeological sites, shipwrecks, buildings, furniture, paintings, sculptures and musical instruments, are made available by the Digital Collaboratory for Cultural Dendrochronology (DCCD)

International best practice and guidelines are developed like the Guide to Good Practice on Dendrochronology

'This document serves as a good-practice guide for the collection and archiving of dendrochronological data in the context of archaeological and historical research. The guide is aimed at both those creating dendrochronological datasets, and those that commission dendrochronological analyses. This guide does not cover the methods involved in dendrochronological analyses, but focuses on how to describe and archive the data and metadata involved in these analyses. This guide is concerned with best practice for the curation of digital information but does not cover the equally important aspects of the curation of physical samples. However, physical samples are the primary source of information in dendrochronological analyses and should always be managed alongside the digital data wherever possible. This ensures that samples can be re-evaluated where necessary and also re-examined as new analytical techniques are developed’ (Website ADS).

DANS has improved and expanded the online archiving system EASY. A map-based search functionality was added that allows researchers a visual way of finding data.

Work was done on the controlled vocabularies of EASY, which are based on the national thesaurus (ABR) and recently updated to a SKOS version by the Dutch Cultural Heritage Agency (RCE). Dutch researchers carrying out research abroad (e.g. Greece) found their way to DANS, and mappings to CIDOC-CRM (Archeo) are undertaken by researchers supported by DANS.

Participation of DANS at projects like ARIADNE and PARTHENOS makes it able to share expertise on topics on data preservation and dissemination within an international network of partners. Revising documentation and policies to continue format monitoring is done with the Archaeology Data Service (ADS) and the Deutsches Archäologisches Institut (IANUS-Forschungsdatenzentrum Archäologie & Altertumswissenschaften). Sharing knowledge with partners in Sweden, Slovenia and Austria about implementing new ways of systematic archiving of data but also the organisational aspects of setting up a repository is mutually beneficial.

The PARTHENOS project empowers digital research in the fields of History, Language Studies, Cultural Heritage, Archaeology, and related fields across the (Digital) Humanities. It provides a thematic cluster of European Research Infrastructures, integrating initiatives, e-infrastructures and other world-class infrastructures, and builds bridges between different, tightly interrelated fields. The motto of PARTHENOS is: Investing in culture is investing in the future!

Developing common policies to ensure the quality of the metadata, data and the repositories where the data is stored is one of the main targets of PARTHENOS. DANS is leading this Work Package. Expected flagship results of the project are:

PARTHENOS is making it possible to position the archaeological community in an interdisciplinary field of sciences and to connect archaeological data for example with linguistic data or historical data. A pan-European infrastructure allows integration of the work previously done by other European infrastructures, projects or initiatives.

Recommendations for European archaeological policies

After 10 years of expertise in the field of long-term preservation of archaeological data, DANS makes the following recommendations:

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