This thesis deals with the specification of geographic information. On the basis
of the role of geographic information as an infrastructure element, a method is
developed for the making of specifications which are well-structured and ensure
the connection between the data collections being part of a joint infrastructure.
The motivation for the presented work is to meet the need for topical geographic
information at any time, so that the requirements for data content and quality are fulfilled, and the information can thus form actively part of the task
performance in public administration as well as in the private sector.
The theoretical background is the establishment of a representational system,
which ontologically comprises a representation of notions in the "real world" and
notions which include the representation of these. Thus, the thesis leans towards
a traditional division between modeling of domains and conceptualization of
these. The thesis contributes a formalization of what is understood by domain
models and conceptual models, when the focus is on geographic information.
Moreover, it is shown how specifications for geographic information are related
to this representational system.
The starting point of the thesis is an analysis mapping the elements in a specification for geographic information. The basis of this empirical investigation is
TOP10DK's data content specification, version 3.2 of the National Survey and
Cadastre. The basic idea is to view a specification as a collection of requirements
and rules, building on terms from the domain and concept ontologies.
In combination with the theoretical basis the analysis is used for developing an
underlying model of notions, which defines the individual elements in a specification and the relations between them. In the chapters of the thesis this
underlying model is extended to include a number of components, which each
contribute to the model being able to form the basis of a strong and productive specification tool for the making and maintenance of specifications for geographic information. These components among others include description of
quality requirements and formalization of rules, so that they can be used for
verification of produced information.
An essential contribution is a formal specification language dedicated to the
formulation of formal rules to be observed by the information. The language is
based on a formal semantic model which makes translation into other languages
possible. In the thesis it is shown how statements can be translated into SQL
and thus form the basis of direct implementation in the production environments
where the geographic information is procured.
To be able to describe requirements for the quality of geographic information is
an essential part of a specification. The thesis contributes a structure of quality
descriptions by introducing two notions: "Acceptable Quality Levels" (AQL)
and "Quality Element Requirements" (QER), which designate respectively the
minimum quality requirements for information produced according to a given
specification and the requirements for the quality parameters used to describe
this information. The two notions are incorporated and related to the developed
system of notions for specification for geographic information.
It is an important part of an infrastructure for geographic information that there
is a connection between the individual data collections. This thesis argues for
ensuring the connection by first and foremost describing these as an integrated
part of the specification work. The thesis contributes a model which describes
relations and dependencies by writing specifications in the context of one or
more other specifications.
As an illustration of the applications of specifications written in the developed
specification language, a concept is developed in the thesis to make possible
a decentralized collection and distribution of information about changes to be
used for updating geographic information.
|Publication status||Published - Aug 2007|