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trouble than they are worth. However, it is not always possible to rely on geometri-
cal grounded properties either because the exact boundary between two features
is unknown, or the boundary is not defined. Consider suburbs within a city. In the
United Kingdom, such boundaries are rarely defined, so if we want to express any
topological properties we cannot use those based on RCC8 or similar geometrically
grounded properties. The message here is that such imprecise properties are very
often useful, should be used with care, and should be used consistently, within a
well-defined context.
6.6.2 M
ereology
Mereological properties are those that deal with the properties concerned with parts
and wholes. If we consider the Ash Fleet Farm Estate, for example, we can say that
it is made from (at least) the following parts: Ash Fleet Farm and Ash Fleet Farm
Cottages. The farm itself can be described as made from the various farm buildings,
fields, woodland, and tracks that make up the farm, and the description is similar
for the Ash Fleet Farm Cottages. So, Ash Fleet Farm Estate can be described as
made from a hierarchy of parts. In fact, if we so wished, we could describe the
whole of Merea as a hierarchical breakdown of the
geographical parts
that comprise
it. However, for two very good reasons such extreme hierarchical decompositions
are not advisable. First, the hierarchy itself will be very large and unmanageable.
Second, although things like Ash Down Farm Estate can be reliably decomposed,
larger areas usually present more of a challenge. This is because something like Ash
Down Farm Estate is a well-defined entity, and through ownership it is reasonable to
think of it as a number of parts that are all owned by the Estate. When we consider
larger areas, things become less clear. In Merea, the national government can be
said to “own” the island, but in the Merean constitution, the government funds rather
than owns the local government. Therefore, while we can describe the topological
property between Merea as whole, and its two main local administrative districts:
Republic of Merea contains City of Medina.
Republic of Merea contains District of South Merea.
we cannot say
Republic of Merea has part City of Medina.
Republic of Merea has part District of South Merea.
at least not from an administrative point of view. We cannot build up a mereologi-
cal description of Merea based on the administrative areas. What we can say is that
Merea has part Medina.
Merea has part South Merea.
Here, we do not refer to the administrative areas but geographical ones. However,
even here there will be problems. If we look below the level of South Merea, it is not
