Computers in the City: archaeological information systems

The work of the Department of Urban Archaeolog57 (DUA) is primarily rescue archaeology (Maloney 1987): the monitoring of planning applications and the preservation or recording of archaeological strata. Recording and excavation is based on the use of the single context, or single deposit, recording system, constituting the basis for an integrated archaeological archive system. The single context system provides a means of rapid data recording and retrieval under the demands of commercial construction programs in the City. More importantly it provides a means by which the very complex stratigraphies found on urban sites can be recorded and interpreted (Harris 1989). Over the last 16 years a vast amount of information has been recorded in the City. 256 sites have contained in excess of 280,000 deposits, a total that is growing by approximately 30,000 deposits a year. From these deposits the DUA has recorded 110,000 contexts with bulk finds, 80,000 special finds and 50,000 ecological samples. All of these data have a record, or several records. Each site has an archive report, photographs and plans (30,000 photos and 100,000 plans so far). And all of this information is referenced to its original deposit (context). An archive is of limited value if it cannot be integrated and recalled in response to any reasonable question. As each piece of information stored by the DUA refers to a site and a context [or a related group of contexts), all associated information can be recalled together through an on-line database. And complex conditional searches can be made on the system to retrieve ever more specific information. Graphic systems are improving access to plans, sections and distributions over the entire City. Increasingly, the archive reports are available on computer allowing quick reproduction or searches for textual information. Computer-aided data acquisition is still very much under evaluation due to the many problems field data entry presents (Boast 1990). However, the DUA is pressing ahead with the use of total stations which has already greatly increased our digitized graphic data. Total stations allow the DUA to process site plans with trench and grid layout at the very first stage of the excavation. With this data on thc computer from the first day of excavation, all subsequent spatial data is recorded in relation to an accurate and checked site plan whose datum and orientation is tied to the National 0s Grid. This allows for future integration of the digitized graphic data into London-wide data presentation systems. Increasingly, the single context is digitized (through Hindsight (Alvey in press) providing single context resolution in text, data and graphics. The DUA has 8 networked multi-user systems running Xenix, a number of PCs running MS-DOS, and stand-alone workstations for graphics, desktop publishing and statistical processing. These systems, split between the field, finds and environmental sections, support 90-110 users. From this ‘platform’ we are working toward increased integration and the development of the relational database for a central on-line archive. The problem for the DUA is not only how to cope with the recording and archiving of this vast amount of information, but how to make it accessible. Accessibility is more than on-line access to databases, access to reports and access to bound context sheets. Access to related information in different forms, and through a