The structured site description provides a means of describing the components of a site (and simple relationships between them) in a way that can be easily processed by a computer, whilst at the same time remaining readable to humans.
An SSD consists of items and attributes. An item is a feature, a find, or the site itself. Attributes include size, location, dating, name etc. A valid SSD must conform to rules specifying how items relate to one another (e.g. a find can be 'within' a feature, but does it ever make sense to allow a feature to occur within a find?) and which attributes can apply to each possible item. It can contain information about location, dating, finds, features etc. and makes use of various 'schemes' for encoding information.
These schemes can be best described by example. Consider some typical entries that could go into a 'dating' field: Medieval, C12th, 1163 AD; terms which could all apply to the same item. We need to specify which dating system is being used - examples are 'period', 'century' or 'year'. It would be possible (but undesirable) to have any number of schemes, but in practice the fewer the better! (We must be able to convert between schemes. For instance, the results of a search for 19th-century churches should include one with a dating value of '1873-1876'.)
For some descriptive terms, a scheme is used with controlled vocabularies to specify which thesaurus or word-list a term comes from. This might allow the RCHME's Thesaurus of Monument Types to be used for describing feature types, and a 'historic buildings' wordlist to provide extra terms describing the construction of a building. Much of the development work lies in picking suitable thesauri and word-lists to adopt; there may be a need for controlled vocabularies to describe quantity and shape, for example.
On a technical level, the approach we propose uses XML as the structure for the description. The rules referred to above are enforced partly through the use of a Document Type Definition (DTD) and through the software used to create and search SSDs.
© Internet Archaeology
URL: http://intarch.ac.uk/journal/issue7/gray/gray3.html
Last updated: Mon Sept 6 1999