Digitizing

All field-recorded information was subsequently imported into digital format. In order to get the maximum level of flexibility from the AutoDesk CAD Overlay® software, a series of layers were created in the master drawing to record each condition. In this way, the conditions can be seen separately or in conjunction with related ones. The joining together of the individual sector images provided a comprehensive visual representation of the surfaces and spaces allowing for further complex analysis of patterns of deterioration relative to location and orientation within the entire space.

	Digitization of graphic field conditions using AutoDesk AutoCAD® software.

Both linear and overall pattern symbols were employed depending on the condition. For example, subtractive conditions such as loss, detachment, delamination, and disaggregation were represented with various linear patterns, while additive conditions such as various surface deposits were represented by point patterns. Within general conditions types, color and patterns were further refined linking subtypes together and/or reflecting the different levels of severity with a type. For example, all repair campaigns were represented in blue. In other cases, graphic symbols were further refined so that linked subtypes were expressed as variations on a specific pattern such as diagonal hatching and cross hatching for detachment and delamination and solid lines for various modes of cracking.

	Screen image of digitized conditions using AutoCAD®.

The flexibility of the software allowed a high degree of accuracy due to the presence of the photomontages underneath the drawings and the software's capabilities to zoom in and out when necessary. The software also can calculate individual condition surface areas which can be linked with other compatible programs such as Microsoft Access® or Arc-View® Geographical Information System (GIS) for further analysis.

To date, a total of 18 spaces have been recorded and all the information has been digitized using this system. The final products are a series of AutoDesk CAD Overlay® 2000 drawings that show the conditions of the spaces. The display of the conditions on the drawings in the context of supporting documentary information such as past uses, treatments or maintenance allows a working prognosis or prediction of causes, trends, patterns, and significance which can later be supplemented and confirmed using other methods or investigation and analysis leading to the point of diagnosis and follow-up treatment, monitoring, and maintenance.

	Example of large format print-out of digitized conditions.

The breakdown of conditions recording into discreet symptomatic descriptions allows for the possibility of positioning correlations between conditions and among variables such as environment, composition, construction, and previous repair. This has been made all the more possible through the ability to better manipulate digitized data as discreet layered information systems with AutoDesk CAD Overlay® 2000.

Both large-scale and individual sector drawings were created. The large scale drawings tend to show the conditions in two main groups: Loss and repair in the upper drawing and other conditions in the lower drawing. Specific designs related to complicated schemes are also shown. A detailed legend, as well as location and orientation drawings, provide reference information. Notes were added for specific annotations done during the field survey.

	Example of individual sector print-out of digitized conditions.

The print-outs of the digitized conditions of the individual sectors are useful to field check the conditions at the site at any time. They are invaluable information to understand patterns of decay, as well as the efficacy of specific past and current treatments. The sectors can be printed out with specific layers such as loss and repair or other related conditions. With this system, conservators can go to the site with valuable information to posit trends and potential cause and effect relationships. Any further intervention from monitoring to protection or treatments should be based on an understanding of the critical parameters affecting change through an initial reading of the existing physical evidence. The graphic conditions survey is an irreplaceable tool that allows the conservator not only a means to record the conditions of the site but also an accurate understanding of its behavior through time affected by a particular context.