Dykes of standards supporting polders of data : The practices used in the Netherlands for making archaeological data available and accessible

In the Netherlands, the archiving and publication of archaeological research data has led to the establishment of EDNA, the e-Depot for Dutch Archaeology http://www.edna.nl/, accommodated at DANS (Data Archiving and Networked Services) http://dans.knaw.nl/en. EDNA is a collaboration between DANS and the Cultural Heritage Agency (RCE). EDNA was set up as a project within the broader organisation of DANS. DANS is an institute of the Royal Netherlands Academy of Arts and Sciences (KNAW) and the Netherlands Organisation for Scientific Research (NWO). DANS serves as the archive for scientific data. Among other services, DANS maintains its on-line archiving system EASY (Electronic Archiving System, https://easy.dans.knaw.nl) which allows researchers to deposit and describe their own datasets. The mission of DANS is to enhance permanent access to digital research data. DANS stimulates cooperation between data producers and users and does research into long- term accessibility. By participating in international projects such as CARARE and ARIADNE, DANS is continuously improving on the options for finding, accessing and re-using (archaeological) data. The existing infrastructure of the e-depot for Dutch Archaeology allows for sharing of good practices such as long-term preservation, data organisation and data dissemination for accessibility. Agreements in order to fulfil this mission have been laid down in the KNA: the quality standard for Dutch archaeology. This is not the only standard which servers to structure and strengthen the Dutch data flow. Datasets are described in EASY using the Qualified Dublin Core metadata standard. The archiving process involves file format migration to preferred formats according to DANS policy with attention to file format aspects for long-term preservation and long-term accessibility. DANS continuously strives for international certification, by means of applying the (self-)audit and assessment of the TRAC (Trusted Repositories Audit & Certification) and by following the guidelines of the DSA (Data Seal of Approval). Additionally, DANS participates in the implementation of a Dutch national protocol of exchanging excavation data. These standards and practices make for the foundations of a successful running service in which durable archiving and unlocking of all digital documentation of the archaeological research is ensured. By 2013, EASY provides online access to more than 20,000 datasets: 17,000 archaeological reports and 3,000 large datasets consisting of data of excavations and explorations (photos, GIS, data-tables, drawings). Both the research descriptions and all data can be downloaded via the online archiving system EASY.