Top plans, once known as daily graphic diaries, are daily printed maps that display the current loci being excavated, exposed architecture, as well as the location of all special finds. Prior to going digital, top plans were traced daily by hand on a light box by the area supervisor.
Special finds were roughly measured in the field using measuring tape and a simple ‘dumpy level’ to measure elevation to illustrate the data mentioned above. The drawbacks of this system are that it is time consuming, lacks precision and accuracy, and is only in hard copy form.
If any type of spatial study was to be conducted, it would require an entire year or more to digitize the top plans into ArcGIS, and the data would still be dependant on the accuracy at which the supervisor or site architect drew the original top plans.
Producing top plans with GIS is a fast process and allows for specially crafted Top plans for each area according to what the supervisor desires to see for the next day’s excavation. The point and polygon data for every area has already been downloaded as shapefiles8 in the DDPL and is directly uploaded to the server to be accessed by the GIS area specialists.
From their networked computer they can directly import the shapefiles into their current ArcGIS project. First, the point data (special finds and elevations) are automatically assigned symbols so that each type of special find can be distinguished visually on the map.9 Supervisors have a printed key of the descriptor codes that they carry in the field. Second, detailed labels for these special finds (e.g. ‘50001 HA Hammer-stone’) are generated on the map.
Depending on the preference of the supervisor, any type of label information can be generated for their point data. Third, the polygons (loci) are imported into GIS. The polygons are assigned different colors according to whether they represent the opening, modification, or closing of a locus.
This procedure allows the supervisor to immediately recognize what new loci were opened the previous day as well as those that were closed. Labels are also generated that can depict dates of the loci or elevation or any other needed information.
Fourth, the supervisors are then called in to look over their top plan and give any input or corrections. The supervisors’ checking of the top plan serves as a fourth check on the entire digital system. Once the drawing of the boom photography of site architecture is finished using the editor tool in ArcMap 9.2 it is ready for GIS analysis.
Since the architecture is already geo-referenced it immediately drops into place on the top plan. The final step of producing the top plan is to update the printing template so that it represents the data collected that same day. The top plans are printed on tabloid size paper over the networked printers.
Multiple copies of different sizes can be produced for the area’s supervisor. From start to finish, daily top plan production averages between 30 minutes to one hour depending on the amount of finds and loci excavated that day.