Kent Archaeological Review extract

Computers and Rescue Archaeology.
by Peter Couldrey.

For several years the digital computer has been employed to assist archaeologists both when planning an excavation and when processing the finds. Much of this work has been of a technical nature and has often passed unnoticed or ignored by field archaeologists. However, the speed and accuracy of a computer are potentially of great value to the archaeologist, especially when applied to rescue excavations where the need for a high-speed labour-saving device is particularly acute. It is the purpose of this note to consider two such applications. The first concerns the preparation of an excavation:

When faced with a notice of a proposed urban development, motorway construction or any other 'rescue' situation, it is often not feasible for the archaeologist to consider excavating the entire area involved. An initial survey must be made prior to the excavation so that sites may be deliberately selected for investigation. This may be done by several methods: aerial photography, field walking, trial trenching or the use of geophysical prospecting instruments. Each of these methods is restricted by considerations such as physical environment, time available and cost. However it is generally recognised that, wherever possible, the most reliable method of surveying is to use several prospecting instruments and to examine the combined results. See Footnote [1] Normally the results from these surveys are in the form of numerical readings taken at points of a grid covering the whole site being considered. In order that these values be intelligible to the excavator, they need to be plotted in the form of a contour or dot-density map. It is this second phase, normally a manual operation taking several days, that may be greatly accelerated by the use of a computer. With data transmission facilities it is possible for the readings from a survey to be typed straight into a computer by use of a terminal situated on the site. The calculations may be made and the resulting map displayed on the same terminal within a few minutes.

Having selected the areas to be investigated, the archaeologist can continue to use the computer effectively both during and after the excavation. Three stages in the recording of results are important: the stratification of layers, the plan of features and the record of associated finds. Typically, layers or deposits are numbered and recorded in a notebook in the order in which they are encountered during the excavation. The exact relationship between them is not always immediately apparent. For instance, a layer encountered in one part of the site and assigned one number may be found to correspond to another with a different number elsewhere on the site. It is then necessary to relate the finds from the two and to make suitable alterations in the notebook. This simple task can be laborious and time-consuming, particularly when applied to a complex urban site; on a rescue excavation, where features may need to be destroyed almost as soon as they are encountered, such a procedure can cause serious delays. By recording details of layers on a computer, updating and altering information can be performed automatically in a few seconds. However, this layer recording system may be further enhanced by including details of associated finds, thus establishing the chronological relationship between the layers. The value of this additional information is that the computer can then be asked to list the contents of a specified layer, the layers and features occurring within a specified period, or the occurrence of any specified class of find. It is during the stage of report writing that this system can prove most useful. The time spent searching through supervisors' notebooks can be considerably reduced by having the information available at the press of a button. Furthermore, by including the position of layers in the form of two-dimensional plots or co-ordinates, distribution maps and site plans may be produced within minutes in a manner suitable for publication. Compare this with the hours taken to prepare a site plan manually!

The work involved in holding details of layers and their associated finds is largely dependent on the amount of detail required to be recorded. If each find is to be recorded individually then, according to the quantity involved, a small team of people may be required to code information throughout the day. If, however, a general summary is satisfactory then one person can probably code the details at the end of each day.

The systems mentioned here have already been successfully applied elsewhere: preparation of excavations at South Cadbury in Somerset involved the use of a terminal on the site transmitting to a computer at Kidsgrove in Staffordshire to process data from geophysical prospecting surveys.See Footnote [2] The distance between the computer and the terminal may seem unnecessarily long, but much depends on the availability of the computer. One of the earliest examples of an on-site recording system used a terminal at a site in Hawaii which transmitted information to a computer at Palo Alto in California by satellite. It is not anticipated that an archaeologist working in Britain should require such an ambitious system.

The operation of both these systems is similar: If the computer is a great distance from the site and data transmission is required, information is prepared using a typewriter keyboard which produces a punched paper tape to be fed through a terminal and the data transmitted, or, more rarely, the data may be transmitted directly from the keyboard. However, if the computer is near at hand and the results are not required instantly, it is cheaper to avoid the transmission aspect of the system by punching the information directly onto some medium, either paper tape or cards, suitable for direct access to the machine. Written results will appear on a printer and maps can be displayed on either a cathode-ray tube (giving a television picture) which may be photographed for a permanent record, or a graph plotter which produces a drawing on paper.

The two applications outlined here are merely two examples of what is possible and much remains open to experiment. Perhaps, once archaeologists have realised the potential value of the computer, co-operation with computer scientists will enable real progress to be made in enabling the mechanical but necessary jobs to be performed by machine while leaving more time for the archaeologist to deal with the essentially manual work of excavating and reprot writing.


Footnote 1.

A R Cox, KAR Number 16, page 22. Return to the paragraph.

Footnote 2.

J D Wilcock, "Science and Archaeology" Number 1 (1970) page 9. Return to the paragraph.
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