2.2 ISO/TC211
45
Data model
The data model contains the data being collected for an application and the services that operate on the data. The data model includes all features and their describing data that make up the complete GIS.
The data consist of the dataset and the metadata.
The dataset includes only the features and their positions.
The metadata is the describing data. The ISO 19115 (Metadata) gives a good
guideline for the selection of metadata. The ISO 19115 pro vi des a standardised list
of metadata elements. The comp1ete list of those elements is given in the annex B of
this book. Further describing elements that are not available in the ISO 19115 may
be mode lied as metadata elements beyond the scope of ISO 19115 or as attributes of
the feature classes.
The programs that use the dataset and the metadata to serve a certain purpose far
the user are called geographic information services. In the ISO 19100 standards it is
stated that services operate on the dataset and reference additional information from
the metadata. Most of the ISO 19100 standards define such services.
Conceptual modelJing and domain reference model
Based on the Conceptual Schema Modelling Facilities, the ISO 19101 sets forth
the process for conceptual modelling, the domain reference model, the architectural
reference model, and profiles.
The conceptual modelling covers the meta model. According to ISO/lEC 14481, a
number of principles govern the use of conceptual modelling and the development of
conceptual schemas. The most important principles are listed below:
1. The 100% principle states that all (i.e.; 100%) of the relevant structura1 and behavioural rules about the universe of discourse shall be described in a conceptual
schema. Thus, the conceptua1 schema defines the universe of discourse.
2. The Conceptualisation principle states that a conceptual schema should contain
only those structural and behavioural aspects that are relevant to the universe of
discourse. All aspects of the physical external or internal data representation
shou1d be excluded.
3. The Self-description principle states that normative constructs defined in the
standards and profiles of the ISO 19100 series shall be capable of se1f-description.
The domain reference model covers the application model and the data model.
The details of domain reference model have been exp1ained above.
The figure 2.5 summarizes the relations between the Meta-model, the Application-model and the Data-model.
45
Data model
The data model contains the data being collected for an application and the services that operate on the data. The data model includes all features and their describing data that make up the complete GIS.
The data consist of the dataset and the metadata.
The dataset includes only the features and their positions.
The metadata is the describing data. The ISO 19115 (Metadata) gives a good
guideline for the selection of metadata. The ISO 19115 pro vi des a standardised list
of metadata elements. The comp1ete list of those elements is given in the annex B of
this book. Further describing elements that are not available in the ISO 19115 may
be mode lied as metadata elements beyond the scope of ISO 19115 or as attributes of
the feature classes.
The programs that use the dataset and the metadata to serve a certain purpose far
the user are called geographic information services. In the ISO 19100 standards it is
stated that services operate on the dataset and reference additional information from
the metadata. Most of the ISO 19100 standards define such services.
Conceptual modelJing and domain reference model
Based on the Conceptual Schema Modelling Facilities, the ISO 19101 sets forth
the process for conceptual modelling, the domain reference model, the architectural
reference model, and profiles.
The conceptual modelling covers the meta model. According to ISO/lEC 14481, a
number of principles govern the use of conceptual modelling and the development of
conceptual schemas. The most important principles are listed below:
1. The 100% principle states that all (i.e.; 100%) of the relevant structura1 and behavioural rules about the universe of discourse shall be described in a conceptual
schema. Thus, the conceptua1 schema defines the universe of discourse.
2. The Conceptualisation principle states that a conceptual schema should contain
only those structural and behavioural aspects that are relevant to the universe of
discourse. All aspects of the physical external or internal data representation
shou1d be excluded.
3. The Self-description principle states that normative constructs defined in the
standards and profiles of the ISO 19100 series shall be capable of se1f-description.
The domain reference model covers the application model and the data model.
The details of domain reference model have been exp1ained above.
The figure 2.5 summarizes the relations between the Meta-model, the Application-model and the Data-model.