temporal classes. MADS (Modeling of Application
Data with Spatio-temporal Features) (Parent et al.,
2008) approaches objects and relationships in its
diagram, with structures very similar to the Entity-
Relationship model. The Perceptory’s model
(Bédard, 1999) was the pioneer in the use of
pictograms. These pictograms are grouped into the
languages Spatial PVL and Temporal PVL (Plug-in
for Visual Languages), which allow the addition of
spatial-temporal characteristics not only to UML,
but also to other visual modeling languages. The
UML-GeoFrame model is based on a structured
hierarchy of classes that make up the GeoFrame,
providing the basic elements present in any
geographic database (Lisboa Filho and Iochpe,
1999).
Finally, Clementini et al. (1993) formally
describe a small set of relationships capable of
reproducing all the possible topological relationships
that can occur between spatial elements with the
representation of point, line or area. This work has
considerable importance in the scope of the
GeoProfile design. Defining a minimum set of
relationships, one eliminates the possible use of two
relationships with different names, but having the
same meaning. This set includes the following
relationships: touch, in, cross, overlap and disjoint.
3 GEOPROFILE
GeoProfile is a UML profile built for the conceptual
modeling of geographic databases. According to the
proposed methods to guide the construction of a
UML Profile (Fuentes e Valecillo, 2004) e (Selic,
2007), two artefacts are generated during profile
development: the domain metamodel and the profile
itself. While the first is useful to understand the
addressed problem, the second presents the
extensions received by the UML metaclasses.
Section 3.1 defines a metamodel for the
geographical domain and section 3.2 proposes a set
of stereotypes for the proposed profile.
3.1 Defining a Metamodel for
Geographical Domain
At the beginning of the metamodel specification,
elements are identified in a conceptual schema,
observing the requirements of this type of
conceptual modeling.
The way each considered conceptual model in
this proposal (GeoOOA, MADS, UML-GeoFrame,
OMT-G and Perceptory’s model) meets the found
requirements was examined. The inclusion of the
main mechanisms present in each of these models
into the GeoProfile allows it to meet most
requirements of a geographic database (GeoDB).
Among the discussed conceptual models, the
UML-GeoFrame shows the closest organization to a
metamodel. GeoFrame is defined in a class
hierarchy representing the elements present in a
GeoDB. Thus, the metamodel development started
from a GeoFrame adaptation (Figure 1).
A GeoDB comprises a number of themes, which
is characterized by the metaclass Theme. A theme
can be formed by the aggregation of other themes or
objects with or without spatial representation,
characterized by the classes GeoPhenomenon and
ConventionalObj respectively.
When one chooses to associate a spatial
representation with objects of a class, it is possible
that the phenomenon is perceived in the geographic
field view (GeoField) or object view (GeoObject).
Depending on the technique used in geographic
information acquisition in the field, its representa-
tion be selected from six options as described in
Goodchild et al. (2007): AdjPolygons, Isolines, TIN,
GridOfPoints, GridOfCells or IrregularPoints.
Representation of geographic objects can be of the
types point, line, polygon or complex (the object
geometry consists of other geometries).
With basis on GeoOOA and OMT-G models,
which provide more detailed solutions for network
representation, Stempliuc et al. (2009) proposed an
extension of GeoFrame to address the requirement.
This extension was incorporated into the metamodel.
The classes in charge of storing alphanumeric
data and information on which elements participate
in the network are represented by the metaclass
Network. Since this metaclass does not have spatial
information, it was defined as a ConventionalObj
specialization. The networks are formed by network
objects (NetObject), which can be nodes (Node),
unidirectional arcs (Unidirectional) or bidirectional
arcs (Bidirectional).
For temporal aspects, the solution proposed by
GeoProfile is to indicate only whether a class is
considered temporary or not, as in the GeoOOA
model. In this way, the metaclass TemporalObject
was added to the metamodel. This metaclass has two
attributes that characterize temporal information.
One of these attributes indicates the temporal type
(validity time, transaction time or bitemporal time),
whereas the other defines the used temporal
primitive type (instant or interval). There are two
enumerations (TemporalType and TemporalPrimiti-
ve) for the possible values these attributes can
assume.
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