Geoscience Reference
In-Depth Information
Fig. 7
The history of an
archaeological site by the use
of TM_TopologicalComplex
(NBN 2
005
)
respect to the excavation time of the complete archaeological site, equivalent
choices can be made. However, instead of a 0D geometric primitive, the 1D TM_
Period is chosen. This allows indicating on which day (eventually supplemented
with the hour) the excavation has started and ended.
Analogue decisions can be made for the second temporal path, the database
time. This can be represented by a TM_Instant, where the temporal position is
relatively measured to a TM_Calendar reference system in combination with a
TM_Clock. Consequently, the position is given as DateTime, thus as the attribute
'dateTime8601'. It can be expected that this time is specified with seconds pre-
cision, since it normally is automatically stored by the database or software. For
the database time belonging to the complete site, two interpretations can be raised.
On the one hand, the database time can be conceived of as the time when a new
database entry is made for the site, and on the other hand, it can be thought of as
the period during which information on the site's objects are entered in the data-
base. Consequently, the first interpretation results in a TM_Instant and the second
in a TM_Period. The determination of the appropriate temporal reference system
remains unchanged.
As illustrated in
Sect. 2.1
assigning a phase of a site to an excavation object is
one of the main tasks in archaeology. Therefore, the third category on which the
ISO standard is assessed is the 'site phase time'. This time is typically a topologi-
cal temporal representation, because a relative ordering is made (Binding
2010
;
Smedja
2009
). The word 'phase' indicates that this temporal value is 1D. Thus,
a TM_Edge should be used. Different TM_Edges, which all represent a certain
site phase, can be aggregated into a TM_TopologicalComplex. Where possible,
the edge can geometrically be realized by a TM_Period. In Annex B of the NBN
EN ISO 19108:2005 standard (NBN
2005
, p. 34) the example of a 'site history' is
given (Fig.
7
). The decisions made above result in the same scheme, although the
different 'OccupancyIntervals', which make up the site's history, are, in our way
of thinking, linked to the individual excavation objects. Thus, the site phase time
characteristic of a complete site will be described as a TM_TopologicalComplex
which is made up of TM_Edges.
