The database unit is the excavation site, namely, the site where archaeological remains have been located. This basic table is connected to others that pertain to interventions, architectural remains, visual material, and bibliographical references.
Data was hosted on the PostgreSQL open-source database, with the PostGIS extension that allows spatial data management. The database was implemented by Geospatial Enabling Technologies (GET).
The database includes all the sites of the published rescue excavations carried out in Athens during the last 160 years within the specific limits of the project. Detailed information on the results of these excavations was obtained from the regular reports in the Archaiologikon Deltion, from various academic journals (PAE, AAA, AE, Hesperia, BCH, AJA, etc.), and the proceedings of archaeological conferences.
The database fields list even the slightest immovable find that was published (e.g. part of a building, a cistern, a workshop, a channel, or a street), namely every physical remain recorded as evidence for the built environment at a given time that was revealed by rescue excavations on plots, roads, median strips, sidewalks, squares, etc.; mobile findings have not been listed. Excavated sites of unpublished rescue excavations are not included in the dataset.
Based on the published archaeological material for the city of Athens, a bilingual vocabulary of semantic terms was created, compatible with acknowledged thesauri and dictionaries that support cultural heritage documentation, such as the Art and Architecture Thesaurus (AAT), the Forum in International Standards in Heritage (FISH) and the Dictionnaire méthodique de l'architecture grecque et romaine.
Important archaeological sites of the city with standing monuments exist within the area covered by the digital map. The configuration of these sites is the result of many years of systematic excavations by the research staff of the Archaeological Service and the Foreign Archaeological Schools. The findings of these excavations are not included in this project, which is why the archaeological sites of Athens appear only as site plans without further indexed information.
The archaeological data for the immovable finds of the published rescue excavations were systematized into manageable information. There are two main classifications: the first is typological and refers to the use of the space; the second is chronological, and classifies the physical remains in terms of the historical period to which they belong.
In terms of typological classification, the initial division into types of use of space is followed by two subdivisions: categories and subcategories of buildings/structures. As the project progressed, a methodology based on specific criteria for data entry was established, which led to the selection of a total of 12 classes of use of space, 65 categories of buildings/structures and 90 subcategories. For example, in the class of Production, we find the category Pottery Workshop with 18 subcategories, such as kiln, cistern, courtyard, etc.
In terms of chronological classification, a selection of 11 historical periods was made, based on the viewpoint of "broader history" (not strictly Athenian). At the next level, the individual dating (by century or subperiod) available for an immovable find is displayed in the results table.
The objective difficulty of documentation on account of the shortage of adequate evidence frequently directs rescue excavation archaeologists to uncertain identifications or dating. When entering data, no attempts were made to interpret what the excavators delivered with reservation.
However, as far as dating is concerned, excavation reports often provide indirect information regarding the lifespan of the remains; we deemed it useful to process these data to extract chronological clues for the undated remains. Indirect information emerges from the stratigraphy of the excavation, i.e. the remains’ chronological context vis-à-vis the rest of the findings in the excavated site: these are the verified time limits, defining either the earliest (terminus post quem) or the latest points in the life (terminus ante quem) of the ancient remains.
Dating based on verified time limits is searchable in the advanced search section of the digital platform for the use of specialized scholars.
The project covers 16 decades of successive changes in the city, with surges in the number of rescue excavations due to construction activity, as in the case during the years 1960-1970. In this context, the need arose to establish a series of cartographic backgrounds.
In particular, as far as the excavation sites' spatial location is concerned, multiple cartographical backgrounds were sought to capture the overview of the city as reliably as possible at different times. These were georeferenced on a case-by-case basis and subsequently incorporated into the Greek Geodetic Reference System EGSA '87, the most basic amongst them being the following:
- Topographic diagrams of 1925 (Municipality of Athens)
- Topographic diagrams before 1936 (Municipality of Athens)
- Topographic maps of 1974, photogrammetrically produced (Ministry of Environment and Energy)
- Orthophoto maps of 2009 (National Cadastre & Mapping Agency of Greece)
- Cadastral diagrams of 2019 (National Cadastre & Mapping Agency of Greece)
IDENTIFICATION OF EXCAVATION SITES
A main task of the project was to locate the excavation site; the plans published in the excavation reports of the Archaiologikon Deltion are beneficial for this purpose. When no excavation plans are available in the publications, which can be as high as 65% of the reports, the excavation address is the only indication of the location/area where the ancient remains were found.
Additional sources, such as the proprietor’s name, the building’s construction date, a general search on the Internet, and on-site autopsy, helped to confirm the spatial identification.
In the case of plots, the boundaries of the excavation site were drawn based on the data of cadastral diagrams. In cases of trenches along roads, e.g. within the framework of public works, the boundaries are depicted by indicative rectangles.
GEOREFERENCING AND VECTORIZING OF EXCAVATION PLANS
In cases whereby an excavation plan accompanies the report, the plan is georeferenced and vectorized according to the following steps:
- Scanning of the excavation plan.
- Digital processing/preparation of the plan to be georeferenced
- Georeferencing of the plan based on the available cartographic backgrounds and as accurately as possible
- Vectorization of the plan – analytical drawing of the scanned file into a linear form
- Designing of the individual remains with polygon geometry
- Linking the aforementioned with the database
In cases of inadequate data regarding the identification of excavation locations (e.g., unclear address) or the georeferencing of plans (e.g., no scale, orientation, or plot boundaries), every possible effort was made to achieve greater accuracy to render the map thorough in terms of archaeological information.
Analytical notes have been kept pertinent to the precise identification of each excavation location, allowing for the appropriate adjustment if new data are published in the future.
DIGITAL CARTOGRAPHIC PLATFORM - webGIS
The digital map shows the association among the archaeological remains in the contemporary urban fabric and allows us to browse the excavations around the city. It provides the possibility of applying criteria for basic and complex searches regarding the general types of space use and the dating of the remains.
Our concern was both the scientific accuracy of the data and the usability of the digital platform, so that anyone interested, whether a lover of archaeology or a connoisseur of ancient topography, has easy access to the data of rescue excavations.