The introduction of microcomputers In 1976 began to change dramatically and substantively the way in which archaeologists record and analyze data. Suddenly, what had been a scarce resource was nearly universally available. As this technology evolves, researchers will be developing applications not yet envisioned.
Word Processing and Desktop Publishing.
Using computer technology, archaeological reports can be prepared quickly and revised conveniently. Archaeologists can now take portable computers into the field to record information at the excavation site. With the advanced capability of software for text manipulation and word-processing software becoming more like desktop publishing software, archaeologists can create reports that include photographs, charts, graphs, diagrams, and drawings in a format ready for publication, substantially decreasing the time between excavation and publication. Powerful new technologies for the dissemination of archaeological information in hypertext format, both on compact disk and on the World Wide Web, are transforming the nature of archaeological publication.
Most archaeological projects deal with vast numbers of artifacts. The use of an electronic database to catalog artifacts improves the efficiency of this essential recordkeeping. It is possible to obtain information about excavated material that was once time-consuming or labor intensive: database management programs can quickly sort and reorganize data, making it possible to query, for example, all objects of a particular material or type, from a particular period, and associated with a particular context. Such processes allow a researcher to detect patterns and relationships and to form hypotheses for further investigation that might not have emerged from a simple handwritten or printed catalog. Optimal results are obtained when the software chosen is a fully relational database system, which allows the user to combine information drawn from several different files or catalogs (e.g., an artifact registry, a pottery registry, a file of information about individual loci). The software should allow the inclusion of graphical information (photographs or drawings) and extensive notation. The ability to export data for use in other computer programs (e.g., for inclusion in reports prepared using a word processor or desktop publishing program or in a spreadsheet or other program for statistical analyses) is very important. Similarly, interactive connections to other computer programs, particularly computer-aided design (CAD) software, are very useful. The context of a particular item recorded in a database can be displayed by a symbol inserted into a drawing to show precisely where the artifact was unearthed. Selecting a particular symbol in a drawing will retrieve the associated information from the database file and display the complete (or selected) material from the catalog. Database management programs easily produce reports that can guide excavation and enhance publication.
Quantitative Analysis and Statistics.
Recording and reporting the presence of materials of a particular type (i.e., cooking pots, lamps, nails) or from a particular period (i.e., Early Bronze II, Iron I, Early Roman), is quantitative information that can be very useful in the interpretive process. If the pottery from a particular locus, to take one example, includes a high percentage of vessels used to prepare and consume food, it could support the conclusion that the area in which it was excavated was a kitchen or dining facility; the presence of a very small quantity of such wares, as a percentage of the whole, would weigh against such a conclusion. Similarly, quantitative information about the ceramics from a particular historical/cultural period can be very revealing. When one period is compared with another, relative quantities of material can indicate an increasing or decreasing population, the extent to which an area was used in a given period, or other changes in the demographics or economy that might have occurred over time. The recording, manipulation, and reporting of such numerical information about artifacts constitutes descriptive statistics, which are extremely important for the careful reporting of archaeological excavation and the effective presentation of conclusions drawn by the investigators.
More important, however, are analytical statistics, also referred to as inferential statistics. Archaeology involves the reconstruction of the human past on the basis of the material evidence, and archaeologists' hypotheses about human activity are based on a very small sample of the surviving material. This may be envisioned as follows:
- 1. Life assemblage. In the past there was a complete material culture, including numerous structures and artifacts that were part of a society of living, active human beings.
- 2. Deposited assemblage. When one cultural environment is replaced by another (whether by abandonment, destruction, or natural evolution), there is a residue from the earlier period of those artifacts that come to rest or remain at the site.
- 3. Preserved assemblage. Only a portion of the deposited assemblage will survive the ravages of time and subsequent activity and be available for excavation and collection.
- 4. Sample assemblage. Only a small portion of the preserved assemblage will actually be recovered and studied by archaeologists.
It is important to note that the several assemblages referred to above become increasingly smaller as the list moves from 1 to 4. This is why analytic, or inferential, statistics are crucial. As the archaeologist theoretically moves from sample data to conclusions about larger populations, there are many computer programs available that will enhance the sophistication and efficiency of statistical analyses.
Computer-Aided Design and Drafting.
CAD (or CADD) software offers great potential for recording and interpretating archaeological data. Related tasks, not treated here, are mapping and surface modeling. Drawings are a staple in archaeological recordkeeping, ranging from simple schematic diagrams, to accurate “stone for stone” drawings of individual areas of excavation, to composite drawings of larger fields or sites. They include drawings of individual artifacts (such as the technical rendering of individual potsherds) and projections of buildings and other structures that illustrate their complete form and function. Electronic (“digitized”) drawings have many advantages over their paper counterparts: they can be more easily edited, more easily combined into larger wholes, and more easily and precisely compared. If drawing to a different scale or combining elements from several drawings into a new, composite whole is needed, it can be accomplished quickly and easily. Furthermore, with drawings produced accurately to scale, measurements of size or distance and calculations of area become trivial tasks, as “overlays” can be easily and dynamically manipulated. As with numerical data, CAD drawings allow archaeologists to engage in “what if” explorations of hypotheses. That can both guide excavation and assist interpretation.
Archaeologists employ several methods to produce CAD drawings. The following are among the procedures in use:
- 1. Tracing. Conventionally produced drawings can be traced, using a digitizing tablet, to produce an electronic copy of the original.
- 2. Scanning. Conventional drawings, photographs, or slides can be scanned to create copies that can be imported into CAD software. Scanning, however, produces rasterized (bit mapped) images that require raster-to-vector conversion in order to obtain drawings that exploit the full potential of CAD technology. Even with the use of autotrace utilities conversion can be very labor intensive and slow.
- 3. Direct entry. A drawing can be generated electronically from directly entered x–y (or x–y–z) coordinates. These coordinates can be obtained and entered manually or directly through linked electronic surveying equipment.
- 4. Photogrammetry. A number of techniques exist for obtaining digital images from conventional film or digital photography. Photogrammetry can produce highly precise graphic images in either two or three dimensions.
Digital Photography and Scanning.
Digital images have become increasingly important for archaeological recording. Whether they are obtained indirectly (e.g. by scanning slides or photographs produced using conventional photography) or directly (i.e, using a digital camera or “frame grabber” and video camera), they offer many advantages over conventional photography. Photographs taken with a digital camera are almost instantly available because they do not require the processing associated with photographic film. Furthermore, digital images, especially those stored on optical disks, are much more stable than images on photographic film. If the electronic data remain intact (multiple backup copies can be maintained to ensure this) the quality of the image will not deteriorate over time. Digital images are also more efficiently kept in archives, where they require far less space and are more easily cataloged and accessed. They can be easily edited (cut, cropped, and enhanced) and quickly imported into documents (from field notes to final publications) or database records. It is quite feasible for a catalog of artifacts, maintained as an electronic database, to include pictures of each object along with text information. Furthermore, digital images can be sent, almost instantly, over computer networks to others throughout the world. Finally, Quick Time™ images, (essentially digital motion pictures) allow an object to be displayed dynamically and seen from all sides and with changing light and shadow, to reveal important detail. Such images can be included with other information as a part of a permanent archeological record or report.
Geographic Information Systems (GIS) and Remote-Sensing and Global-Positioning Systems.
Several computer technologies have had an impact on archaeological data collection and interpretation. Geographic information systems (GIS) provide a dynamic link between computer-generated maps or CAD drawings and database files. Thus, the location of any item in a database file can be shown on a map or drawing. Similarly, objects on a map or in a drawing can be linked to related information in a database file. Furthermore, GIS software allows the researcher to explore the spatial relationship of objects to each other as well as to other spatial relationships. Using a survey map and its associated data, relationships can be explored among occupied sites along with their relationship to such ecological and topological features as the availability of water, the proximity of roads, and the nature of the terrain. Similarly, the plan of a building can be used to show the relationship of the artifacts found in it, providing the archaeologist with data to determine the kinds of human activity that took place in it and in its vicinity after it was destroyed or abandoned. Remote-sensing and global-positioning systems offer the archaeologist means for more rapid and accurate data collection and recording, particularly during surveys, than manual techniques allow.
Advances in computer technology are encouraging archaeologists to adopt standards for data collection and recording and to share information more easily. Computer software programs are facilitating the collection and storage of data and enabling the results from many excavation projects to be drawn together to enhance the understanding of increasingly wider geographic regions and more extended periods of human history.
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Archaeological Computing Newsletter. Published quarterly by Oxford University's Institute of Archaeology, this newsletter contains brief articles reporting current work in archaeological computing.
CSA: Newsletter of the Center for the Study of Architecture. Published quarterly by the Center of Architecture at Bryn Mawr College, this newsletter covers a broad range of computer applications of interest to archaeologists and very often includes information about classical and Near Eastern archaeology.
Thomas R. W. Longstaff