Page 123 - Green - Maritime Archaeology: A Technical Handbook. 2nd ed
P. 123
102 Maritime Archaeology: A Technical Handbook, Second Edition
B
A Bad fix
A
C
BC
Good Fix
Figure 4.7 Strong and weak fixes. In the upper diagram, the fix is weak, and a small varia- tion in distance will cause a large error. In the lower diagram, lines of intersection cross at right angles giving a strong fix.
dimensional rectangular coordinate survey system or “bed frame” was established over the site. This was done by driving stakes into the ground at 1-m intervals along the baseline. Between a pair of these stakes, a bar was set up and leveled with a spirit level. A pair of bars was then mounted extending horizontally and at right angles to the baseline 6m across the site to a second pair of stakes. Using a carpenter’s level the framework was
