# From Field Archaeology to Virtual Reconstruction: A Five Steps Method Using the Extended Matrix
## 2 Results: A Standardised \"Five Steps\" Protocol
### Data Collection (1/5)  
The reconstructive process begins with the study of the archaeological and historical context (see Figure 2) through excavation, source collection, survey, and digitisation. Comparisons with similar contexts, belonging to the same geographical area and historical period, are a valid reference for the reconstruction. In this phase it is important to pay particular attention to the visual quality of the models representing the real data (obtained using digitization technique such as laser scanning or photogrammetry) as this has an important influence on the richness of the information available for the reconstructive hypothesis. The model should be a _digital replica_[24] (a model with a high visual resolution suitable for real-time simulation) allowing the relevant elements of the original context to be clearly perceived and recognised (e.g., colour, shape, dimensions). In other words, the reliability of archaeological interpretations is strongly influenced by the meticulousness of the work of collecting and managing archaeological records and data. According to the third principle of the London Charter in fact, \"_in order to ensure the intellectual integrity of computer-based visualisation methods and outcomes, relevant research sources should be identified and evaluated in a structured and documented way_\" [10]. All the archaeological reports must be kept into account before designing a reconstructive hypothesis, however, being the remains insufficient to reconstruct an entire context, other fundamental sources should be examined and used to improve the quality of the work and mitigate the \"shadow area\":  
* digital replica of archaeological site (3D survey techniques such as photogrammetry or laser scanners are fundamental to obtain accurate metric documentation and effective digital models);
* photographic documentation and excavation reports;
* historical documentation and testimonies (including historical paintings and designs, archive photographs, cadastral map, archives, registers, deeds, etc.);
* architectural studies on ancient buildings, architectural styles, theoretical rules of construction, theory of proportions and modules;
* structural analyses and simulations;
* dating and archaeometric analyses;
* comparison with other buildings still preserved and showing similar stylistic, structural or functional solutions.  
The information collected should be stored in a list of sources (see _infra_ Table 2) and provided with an identifier. In the EM 1.2 this identifier consists of a \"D\" (which stands for \"document\") followed by a dot and an incremental number (D.01, D.02,..., D.\(n\)).  
This data structure will make it easy to collect information (from physical libraries or online database) and to reuse it in the Extended Matrix. A \"key\" field, to be filled in, is \"properties\": here, specific features, obtained from the source and testifying useful information for the reconstruction (such as shape, colour, dimension, function, style, etc.), are annotated.  
This is a fundamental step that lays the foundations for the subsequent interpretative work. The right amount of time should be allocated to this phase, bearing in mind that the whole process is iterative and going back and add sources to the list is always possible (the Extended Matrix is conceived to assist users to develop interpretative hypotheses within a \"non-destructive\" expert system in which it is possible to modify the information involved in the different phases).