Page 167 - Green - Maritime Archaeology: A Technical Handbook. 2nd ed

146 Maritime Archaeology: A Technical Handbook, Second Edition
was further evaluated in an underwater environment (Green and Gainsford, 2003).
The trials were based on a rigid, 2 m2 photo tower (Figures 4.27 and 4.28) which was used as a calibrated testbed for the project so that intercompar- isons of land-based and underwater measurements could be made. Eigh- teen targets were set on the tower, eight (1–8) on the base, four (9–14) at about 0.6 m above base, two (15 and 16) at 1.1 m above base, and another two (17 and 18) at 2.2 m. The students were divided into two teams to carry out measurements in the different environments with the different systems.
1. Definitions
It is important to understand the terminology used in survey because, unless one is quite clear what is being said, a great deal of confusion can occur. There are a number of basic terms that need to be defined. The following are based largely on Kaye and Laby, (1966).
Figure 4.27 Photo tower on land shown in the mark-up mode of PhotoModeler interface.