Linguaggi dichiarativi per la ricerca archeologica

This article presents a detailed overview of the principal languages for the representation, interchange and exploitation of data, both textual and graphical. In particular, a detailed discussion is made of the procedure of text encoding. The approach taken in the article emphasises the importance of the World Wide Web for data dissemination and the fundamental issue of standards: HTML, XML and its derivate languages are analysed in detail. Importance has been given to the languages that represent not only the characters that textual sources contain but also the structure, content and appearance of the data. Two types of markup languages are presented: procedural and descriptive. A procedural markup specifies how the document should be presented. Descriptive (or logical) markup languages describe the structure of a document, such as SGML. The article considers the topics of international standards as the TEI Guidelines for Electronic Text Encoding and Interchange for the description of marked-up electronic texts and the RDF metadata recommendation. The first section concludes with a presentation of the innovative aspects of the Semantic Web. The second part focuses on spatial, graphical and multimedia data, and their display and exchange over the Web. The development of the Geography Markup Language (GML) is introduced and discussed, as well as other vector formats derived by XML, such as SVG, to construct structured spatial and non-spatial information for data sharing over the Web. Importance has also been given to the virtual reality languages such as VRML, an ISO standard, and the XML-based X3D. In conclusion the article aims to present a broad view not only of the technical aspects of data encoding but also the analysis of the standards, which are fundamental in the light of data interoperability and exchange