Internet Archaeol 15. Armin Schmidt. Geophysical prospection

3. Geophysical prospection

3.1 Measurement and data recording

The development of geophysical instrumentation is closely linked to the rapid improvement of data recording hard- and software. Only the copious storage capacity and convenient operation of the latest instruments have made the geophysical prospecting of large areas possible. Even a small Ground Penetrating Radar (GPR) survey can produce gigabytes of data that are only manageable with modern computing equipment. Prevailing survey procedures pertinent to different geophysical disciplines also had a profound influence on the design of data loggers. Geophysical surveys for geological purposes tended to be carried out along long lines that were fairly widely spaced. Accordingly, data recording is undertaken with line and point numbers stored individually for each data point. In contrast, archaeological geophysical surveys are usually carried out on a regular sample grid and the position of a specific measurement is hence determined by counting all readings from the start of a grid. These different frameworks of data recording are perpetuating themselves, as practitioners who are used to one system are often reluctant to adopt instruments that use a different method of data logging.

With the miniaturisation of computing devices the intelligence of data loggers has increased dramatically. LCD screens that show trace plots as the operator walks along a line are already implemented and greyscale displays that fill as a survey progresses have been suggested (M. Noel, pers. comm. 1999).