New Approaches to Working with Old Maps Computer Cartography for the Archaeologist

Abstract

The archaeologist can have virtual mastery over original site maps. The end product is the result of the surveyor's technique and the cartographer's drafting abilities. Archive materials, on the other hand, offer challenges that the archaeologist does not encounter with original illustrations. The problem lies in the interpretation of old maps, plans, and drawings which differ in scale and represent different kinds of information. It is, furthermore, difficult to publish these records with consistent standards of precision, style, and focus when the survey, excavation, and record-keeping were done by someone else, with varying degrees of accuracy, for different objectives. The challenge, then, is to thoughtfully consider ways to overcome the idiosyncratic publication styles, perhaps inaccurate surveying, and variability in scale and detail of these maps for purposes of analysis and redrafting. Standardization is best achieved with the use of computer drafting tools. The theory of computerized archival cartography depends on two assumptions. The first is one of definition a map is an illustration of some geographical reality, and like any illustration it is potentially unlimited in its capacity to represent a variety of data related to a geographically defined area. Map analysis is successful only when the cartographer determines what information it is representing is the most relevant to the study at hand. The second assumption is one of technique the use of the scanner is the only practical way of translating a printed illustration into a form the computer recognizes and can manipulate. The bitmap images, however, will never achieve the clarity and quality of the original illustration. This limitation must be kept in mind when reworking old maps by computer. Scanners, like all computers, are digital. That is, they transform the image into pixels (dots) representing values of 0 and 1. The result is much like recording a song taken from the radio regardless of the quality of the equipment used, some information will be lost in the process of translation, and some blurring of sound (or image) should be expected.