4. Cricklade: A Practical Archaeological Application of SVG

4.1 The Cricklade Publication

This section will look at some of the practical problems for converting archaeological vector drawings into SVG, and how to make the drawings more interactive by using JavaScript to control layers. To demonstrate, AutoCAD drawings prepared by Guy Hopkinson for the Internet Archaeology publication 'Excavations at Cricklade, Wiltshire, 1975' by Jeremy Haslam (2003) were used. As published, the drawings are viewed with AutoDesk's Volo View Express software. Volo View Express (like AutoDesk DWF Viewer, which has recently replaced it) is designed solely for use with Microsoft's Internet Explorer web browser, and Microsoft's Windows operating system. Because AutoDesk only makes its products available for Windows, it is often assumed that those interested in accessing CAD drawings on the Web will be Windows (and therefore Internet Explorer) users anyway (Watt et al. 2003, 925). This is short-sighted at best, and at worst perpetuates the view that reliance on a particular vendor is sufficient for the healthy development of the Web. As an open source, XML-based markup language, SVG will be explored as a possible alternative to this proprietary solution.

The site of Cricklade is part of the 9th-century system of Saxon urban fortresses and is located in Wiltshire, England. The defences show the rectilinear planning typical of this type of defensive structure, and it is in a good state of preservation. The site has been well researched by both archaeologists and historians, and in 1975 excavations were carried out in advance of housing development. Work was concentrated on two main parts of the western half of the site. Site A looked at an area inside the defences, which showed occupation was continuous during the Roman period, and Site B was an excavation carried out on the defences themselves. The excavation showed that the defences were removed, repaired and rebuilt several times up through the medieval period. In addition to photographs and written analysis, the work produced a series of plan and section drawings to document this complex sequence (Haslam 2003).

In July 2003, the article 'Excavations at Cricklade, Wiltshire 1975' by Jeremy Haslam was published in Issue 14 of Internet Archaeology. Because this article published the findings of excavations carried out in the 1970s, inclusion in Internet Archaeology was an experiment in 'retrospective conversion' or 'retrospective publication', which is the process of digitising existing hard-copy archaeological drawings (Eiteljorg et al. 2002) The twelve ink-on-permatrace drawings from Cricklade were large format, with some over 1.5m long. If published at the time, the drawings would have been scaled down for inclusion in a print publication (Hopkinson and Winters 2003). In print, this publication would most likely have appeared in a regional journal, which would be small format (less than A4) and unable to accommodate large plan and section drawings because of the costs involved in producing foldout images. (Judith Winters pers. comm. July 2003). Electronic publication, specifically using vector graphics, has allowed the presentation of these drawings in their entirety.