Geoscience Reference
In-Depth Information
Table 5
Pros and cons for the application of the NBN EN ISO 19108:2005 (NBN
2005
) model
for temporal ordinal reference systems, the variants of Cox and Richard (
2005
) and Michalak
(
2005
) to the archaeological time scale
Cos and Richard (
2005
)
Michalak (
2005
)
Adaptation
ISO (2002)
Geometric
Topological
Topol
+
aeom
# Classes
2
3
3
5
# Compositions
2
2
1
1
4
# Associations
2
2
# Inheritance
1
2
4
# Interfaces
1
1
1
2
+
+
Simple
+
Division between era
and boundary
+
Order explicitly
defined by
associations
+
Completely
topological
+
Extendable
by geometry
+
Division between era and
boundary
+
Order explicitly defined by
associations
+
No explicit temporal position
required
−
−
DateTime
requires
precisely
known date
−
More complex
−
No geometric
information
−
Multiple
inheritance
−
Use of 'Position',
implicitly only fixed
dates possible
−
Multiple
associations
−
More complex
(Michalak
2005
). The model proposed by Michalak (
2005)
is shown in Fig.
12
.
The boundaries of an ordinal era are in this variant as well explicitly realized by
adding the class GL_OrdinalTopolNode (Fig.
12
). Both GL_OrdinalTopolEra and
GL_OrdinalTopolNode are subclasses of TM_TopologicalPrimitive and inherit
from this class the interface TM_Order, which allows returning relative temporal
positions. The optional attribute 'alias' enables the use of different names for the
same era or boundary, comparable to linking to a thesaurus.
The application of Michalak's (
2005
) model on the archaeological time scale
is depicted in Figs.
13
and
14
. According to an example given by Michalak for
the geologic time scale, part of the archaeological time scale is first schematically
drawn in Fig.
13
, which shows the temporal edges and (shared) nodes. This Fig.
13
graphically depicts the structure of the model described in Fig.
14
. In Fig.
14
,
five temporal ordinal eras and their initiation and termination associations to five
ordinal topological nodes are given. Geometric realizations are not included in this
example. This model allows defining a temporal ordinal reference system when
the positions of the temporal boundaries are not known (exactly). At the other
hand, specifying the temporal position of (one of the) boundaries remains possi-
ble by the geometric realization association from the topological to the geometric
primitives.
The three applied temporal ordinal schema variants all have pros and cons,
which are summarized in Table
5
. The first part of this table shows the complexity
