The process of digitising differs widely from larger excavations, evaluations, watching briefs, and the like. Larger excavations such as Villa Magna will most often entail a data entry stage at the beginning of the process, to ensure all plans/sections are recorded within the database. Both plans and sections should be digitised in this each case.
Data Entry
When using the ARK recording system, all plans/sections should be entered in the database prior to digitising. This often involves assigning a plan/section number to each drawing. For more details of data entry procedures, please see the ARK user documentation.
Scanning and Georeferencing
After the necessary information has been entered in the database, the plan/section can be scanned and georeferenced. When using ARK, georeferenced plans and sections should be saved according to the accepted naming conventions. It is important these files are saved correctly to ensure the proper functioning of the ARK database.
The georeferencing of plans is fairly straightforward, usually relying on the corners of the permatrace as known points within the site grid. Georeferencing of sections is a more complex process, as sections do not hold Cartesian X,Y coordinates similar to plans. As such, sections are georeferenced inputting manual points. The first georeferencing point uses a starting X coordinate and the elevation at that coordinate (ie the benchmark for the section). This would take the form of (100, 65.27m). The second point is determined by adding the length of the section to the X coordinate, and leaving the benchmark value the same, taking the form (100+X, 65.27m). Sections may end up overlapping using this system, so definition queries will be used to display single sections.
Digitising
After the plans to be digitised have been scanned and georeferenced, the necessary data must be added to ArcMAP. This consists of a series of shapefiles or feature datasets. The exact process of digitising is dependent on whether plans or sections are being drawn, but generally involves using the Editor toolbar to draw lines copying the georeferenced plan or section. These lines, polygons, and points are then attributed with the necessary SU, symbol, and source information.
Digitising for Villa Magna will involve many different team members, each working in an individual geodatabase. When individual work has been checked, it can then be uploaded to the master excavation geodatabase and imported into ARK. The sooner records are digitised, the sooner they will be visible within the digital record, making concurrent data entry and digitisation more valuable.
It is important that all data is checked carefully when digitising, as incorrectly attributed features can greatly alter the appearance and accuracy of the digital record. Users unsure of georeferencing, editing, or the basic digitising conventions are encouraged to read the relevant sections of the ARK Help wiki or consult a member of the team more familiar with the process as often as needed to ensure the digital record is an accurate reproduction of the paper archive.