As the survey progressed, the data from all the grid squares were meshed together to produce a composite image across the whole site. Reading the results of any geophysical survey is difficult and requires an experienced geophysicist working together with the site's archaeologist. The geophysicist understands what causes anomalies and is able to identify those caused by ancient activity. The archaeologist refines their interpretation on account of his or her knowledge of the site or period in question. Interpretation usually relies on archaeologists subjectively picking out buildings, wall alignments and other features which they might recognise from other sites or from plans they have seen in books.
Unusual anomalies can therefore sometimes be very hard to interpret.