Page 212 - Green - Maritime Archaeology: A Technical Handbook. 2nd ed

Chapter 6: Photogrammetric Techniques 191
Figure 6.14 Small finds target markers shown with a 20-cm scale. Targets were used to mark small fragile objects that were removed from the site. (Courtesy of Jeremy Green, Depart- ment of Maritime Archaeology, Western Australian Maritime Museum and of the Institute of Nautical Archaeology, Bodrum, Turkey.)
light-weight, 1-m square grid made of plastic water pipe with 100-mm graduations marked on the piping; the second was a rigid, 1-m square grid made from steel square-tubing, graduated with 200-mm graduations.
This control grid system was also useful where objects were located on holes or under rock shelves. The grid again acted as a secondary control system so that the photographer could concentrate on first obtaining views of the grid and the object and then the grid and the primary control system. Obviously there were situations were PhotoModeler could not work, for example, when an amphora was orientated with its mouth facing downward. In this situation the camera could not see the whole mapping label and pho- tographing one or two of the spot points together with the toe or attempt- ing tape measurements were tried.
1. Cameras
In the 1999 and 2000 seasons, the Nikonos system was used. In 2001 a digital camera in a custom-built underwater housing was used. The two systems make an interesting contrast in the ease of operation and the