Geoscience Reference
In-Depth Information
Fig. 8
Topological structure
of the Harris matrix
relationships:
a
unlinked,
b
later/earlier than,
c
equivalence
a certain period of an archaeological time scale is given. Based on this descrip-
tion, the decision for a geometric representation can be made, because informa-
tion about the position in time is known. The assessment between 0D and 1D is
connected to which this characteristic refers. When it refers to a usage period, the
choice for 1D seems obvious. However, the reference is made to an archaeological
period, which could be of long duration or even longer duration than the period of
usage. In the latter case, you should then refer to the same period for both begin
and end node. Therefore, there is opted for a 0D representation. The reference sys-
tem to which the temporal position is defined is a temporal ordinal reference sys-
tem. Such a temporal ordinal reference system could be specified in general and
then reused in other projects, by other teams, etc. For the application of the NBN
EN ISO 19108:2005 structure of this reference system to the archaeological time
scale used in Western Europe reference is made to the
Sect. 5.2
. Regarding the
archaeological time of the site, a 1D topological primitive will be opted for, since
the occupation of the site can have been continued for more than one period of the
archaeological time scale. In this case, the temporal ordinal reference system will
be used too.
Finally, the sixth category is the absolute time. Absolute dates are mostly the
result of scientific analysis, such as radio carbon dating. Although these dates
are absolute, they comprise uncertainty, often expressed as probability. The
choice for a geometric 0D representation is evident. The temporal reference sys-
tem to identify the position can be the Gregorian calendar, since absolute dates
are usually specified at year level. However, no structure to express the uncer-
tainty or probability of these kinds of dates is available in the NBN EN ISO
19108:2005 standard. The only possibility is the use of the enumerated data
type TM_IndeterminateValue (Fig.
6
). This data type can be used in combina-
tion with a temporal position which uses another temporal reference system than
the Gregorian calendar or the UTC. Therefore, a better option could be to create
