Before 2010 at PARP:PS we drew 1:20 scaled drawings by hand on A3 size mylar paper.
The outlines of the trench are not standard grid squares. That is impossible with the amount of standing architecture and our desire to get to the foundation of the existing walls in order to date their construction. Our trench outlines are defined by the rooms in which we are excavating. So we measure by baselines, usually a line (or two) down the center of the trench.
The first drawing of the series records the baselines and succeeding mylar pages are laid on top of this baseline drawing; the baselines are traced and the features are drawn in.
At the closing of a trench we are left with, say, 30-40 drawings of each trench that have very little relationship with each other except for the baseline. Other large architectural features were not traced into each drawing and so one had to put all of these mylar drawings together to be of much use. And that was the plan: to assemble these mylar sheets in Illustrator and make a final clean drawing of the trench for research and publication. But that was rarely completed and even then, the Illustrator drawing would have to be added to the CAD plan at some point and georeferenced. So even if this worked at peak efficiency, it would require many hours of post-field work to get a clean set of CAD plans for the project.
The 2010 drawings were made much simpler by the use of iDraw on the iPads to make our drawings. There were some issues with the early versions of iDraw. You could not zoom more than 400%, there was a fixed paper size, there was no grouping, and the unit of measure was in pixels. You couldn’t even rename the layers. But we found ways to work around most of the issues and software updates (even while in the field) fixed several of the bugs that we encountered.
The advantages were that we could duplicate one drawing, delete what we didn’t need, and add what we did. Major architectural elements that remained visible for days at a time were kept in from day to day and when the stones were removed from the trench they were removed from the drawing.
The 2010 drawing workflow was also integrated with the ongoing CAD work. We have a survey supervisor (Syd Evans) who operates the total station and an project architect (Helen Turner). The architect and the surveyor worked together to place the baselines for each trench and to shoot and draw the initial location of the walls that would form the extremes of the trench. The resulting CAD drawing would then be exported as an image file by trench, placed in iDraw and traced. All other features were measured and drawn in iDraw by the excavation team as they would draw their normal plans. Reference points, including any substantial architectural elements would be measured by the surveyor, and both the total station points and exports from iDraw would be given to the architect to make the final clean drawing. The architect is the one who would spot any discrepancies and report those back to the team.
This dynamic interaction between the surveyor, architect, and field team was never possible in the old system. If the team only ever draws in the field and one has to try to fix any errors after the season, mistakes cannot be corrected easily.