Figure 5 Conceptual schema of temporal position ISO, 2002
4. METHODS
The proposed method for the analysis of the ISO 19108 standard’s applicability in the domain of archaeology is centred
on the six temporal paths identified by Katsianis
et al
. 2008 Table 1. These temporal categories can be assumed to
represent the most common set of time indications, which are applied to 3D archaeological excavation objects. Therefore,
they are required in a 4D data model for archaeological data which ought to reuse parts of existing standards and data
models. For each of the six categories Table 1 the ISO 19108 standard
2002 is examined in order to assess its suitability. An appropriate standard-conform description of each of these
temporal paths is determined. For this purpose, several assessments must be made. First, ISO 19108 2002 gives the
choice between the geometric and the topological temporal representation. Second, irrespective of the preceding choice, the
decision between a 0D and 1D representation has to be made. Thus, the temporal value can be geometrically represented by
TM_Instant or TM_Period Figure 2 or topologically by TM_Node or TM_Edge Figure 3. Finally, an appropriate
temporal reference system to which the temporal value is relatively measured has to be chosen Figure 5.
Since the ISO 19108 standard 2002 mentions archaeology explicitly as one of the applications where an ordinal temporal
reference system is more appropriate than another temporal reference system p. 20, this part of the standard is applied to
the archaeological time scale. Multiple archaeological time scales exist based on different spatial or cultural regions. In this
paper, the archaeological time scale for Western Europe is used. Although different versions occur, the main periods and
subperiods are largely accepted. However, begin and end dates vary according to the spatial location andor are not exactly
known. In the example used in this paper, the choice is made to use dates described by the Flemish Heritage Agency
https:inventaris.onroerenderfgoed.be, 160513 and about which general acceptance as rough dates for the Flemish region
exists. Similar research is done for the geological time scale by
Michalak 2005 and Cox and Richard 2005. Although both of them presented almost simultaneously a temporal model for
the geological time based on ISO 19108, two different results were obtained. Michalak 2005 adapted the structure of the
Temporal Ordinal Reference System ISO, 2002 with topological elements. Cox and Richard 2005, on the other
hand, developed the system with geometric elements. In this research, the ISO version of the temporal ordinal reference
system as well as the adapted versions of Michalak 2005 and Cox and Richard 2005 will be applied to the West European
archaeological time scale. To clarify the differences between the three variants, only a part of the archaeological time scale is
used: the Roman time including three subperiods Early, Mid and Late Roman time and the Middle Ages.
The prefix ‘TM_’ is used where classes of the original standard are used. After the
comparison of the pros and cons of each of the models, a proposal will be given about the most sufficient system for the
West European archaeological time scale.
5. RESULTS AND DISCUSSION
Kategori