Spent two very enjoyable half days at Westleton. On Sunday, met up with David Sims to record a crawl trench system I have already mapped. However this time we mapped it with the traditional method of tape (using a 50 mtr tape) and offsets. This was a learning exercise for me. Mapping this way produces a more accurate plan than the way I usually map with a GPS. However it is very time consuming - it took two of us 4 hrs to map the system as opposed to just under an hour I sepnt using a GPS sometime last year. On Mon spent a half day mapping another crawl trench system just using the GPS this time. I compared two methods of recoding by GPS: (1) by marking changes in direction of the trench with way points then 'joining up the dots'. (2) by recording the trench using a track. Of the two methods I find using way points to be the most accurate. However if way points are too close together odd results can arise so it pays to make a rough sketch as well to help in prod...