An essential element of ArcGIS for INSPIRE is the Enterprise Geodatabase (GDB) template. The GDB implements the application schemas of the abstract INSPIRE data models, per Annex I theme and part of the Annex II/III data themes.
To install the INSPIRE geodatabase, follow instructions in the InstallationGuide_ArcGISForINSPIRE_GDB_10_6_EN.pdf document. After installation, see the use case documentation for how to set up and use INSPIRE View Services, INSPIRE Feature Download Services, and INSPIRE Predefined Dataset Services.
INSPIRE geodatabase implementation
The implementation of the INSPIRE application schemas in the geodatabase relies on encoding rules describing how to translate the abstract INSPIRE data models into the physical implementation in the INSPIRE template. The INSPIRE geodatabase template supports the publication of INSPIRE View and Download services and respective underlying datasets.
In the following table, the main encoding rules are listed and discussed.
An INSPIRE spatial object is typically represented as a feature class in the geodatabase. In cases where a spatial object does not have a geometry property, an object class is used instead.
The INSPIRE spatial object type AdministrativeUnits::AdministrativeUnit is stored in the geodatabase in the feature class auAdmUnitS.
The INSPIRE spatial object type Addresses::Address is stored in the geodatabase in the object class adAddress.
Names of feature classes, object classes, and fields are limited to 30 characters in the geodatabase. The names from the application schemas are therefore typically shortened in the geodatabase. To simplify the mapping between the names and to guarantee uniqueness, all names in the geodatabase start with the short code of the application schema that contains the type.
The INSPIRE spatial object type AdministrativeUnits::AdministrativeUnit is stored in the geodatabase in the feature class auAdmUnitS. The short code for the application schema AdministrativeUnits is au.
Each feature or object class has two fields with identifiers. Both are integers. The OBJECTID field is an internal identifier, used only for the management within the geodatabase. It is automatically set by the database upon insert. The IFCID field is the identifier used in foreign key relationships. It must be set upon insert into the database by the transformation process adding data to the geodatabase. It must be unique for the feature and object class within the geodatabase and for the INSPIRE spatial object type.
Attributes of an INSPIRE spatial object type with a maximum multiplicity greater than one are converted into their own object class. The attribute values are associated with the spatial object through foreign key references (RID field) to the associated feature or object class (IFCID field). Only by using this mechanism is it possible to have a general representation of multiple attribute values in a geodatabase.
The attribute name of the INSPIRE AdministrativeUnits::AdministrativeUnit spatial object type is converted to the auAdmUnitS_name object class. The object class contains all information from the value data type of the attribute. In addition, it contains the RID field that references the entry in the auAdmUnitS feature class that the name belongs to.
INSPIRE distinguishes between properties where the value is unknown to a data owner (value type void) and where the data owner knows that the property is not applicable for the particular spatial object (for example, a road without a road name). These cases have to be distinguished also in the geodatabase. In the INSPIRE application schemas these properties are marked with the stereotype <<voidable>>. An additional field with the suffix _void is added to the geodatabase in these cases.
Attributes with a data type that is marked with the stereotype <<codeList>> in the INSPIRE application schema is converted into two fields.
The nationalLevel attribute of the INSPIRE spatial object type AdministrativeUnits::AdministrativeUnit is converted to the nationalLevel field and nationalLevel_cl field. The field nationalLevel contains a value from the code list AdministrativeHierarchyLevel, for example, 1stOrder. The nationalLevel_cl field contains, for example, the URL http://services.interactive-instruments.de/download/cl/AdministrativeHierarchyLevel.xml.
Attributes with a data type that is marked with the stereotype <<enumeration>> in the INSPIRE application schema is converted into a single field. The field contains the value from the enumeration, which is represented in the geodatabase in a domain.
The legalStatus attribute of the INSPIRE spatial object type AdministrativeUnits::AdministrativeBoundary is converted to the legalStatus field. It contains a value from the enumeration, for example, agreed.
For attributes with a value that is a structure data type, (it is marked with the stereotype <<dataType>> or <<union>> in the INSPIRE application schema), all attributes of the data type are converted separately. Be sure that all names are unique.
The inspireId attribute of the INSPIRE spatial object type AdministrativeUnits::AdministrativeUnit is converted to the fields id_localId, id_namespace, id_versionId, and id_versionId_void.
Some INSPIRE spatial object types allow instances to carry a range of different geometry types (for example, either a point, a line string, or a polygon). In the geodatabase this requires using separate feature classes depending on the geometry type. As a result, these INSPIRE spatial object types are converted into multiple feature classes with different geometry types. To maintain uniqueness of the feature class names and indicate the geometry type, a short code is added to the end of the feature class name: P for points, MP for multi points, L for line strings or multiline strings, and S for polygons or multi polygons.
The property geometry of the INSPIRE GeographicalNames::NamedPlace spatial object type is of the GM_Object (an arbitrary geometry) data type. As a result, the spatial object type is converted to gnNamedPlaceP, gnNamedPlaceMP, gnNamedPlaceL, and gnNamedPlaceS feature classes in the geodatabase.
There are spatial object types in the INSPIRE application schemas that have multiple geometry properties. In the geodatabase, however, every feature class may have only one geometry property. In these cases, an additional feature class is added that references the main feature class using a foreign key reference (RID field).
The INSPIRE CadastralParcels::CadastralParcel spatial object type has two geometry properties, geometry and referencePoint. The geometry attribute is converted to the SHAPE field in the cpParcelS feature class and the referencePoint attribute in the SHAPE field in the cpParcelS_refPoint feature class.
Data types with geometry properties are converted to feature classes not object classes.
The AdministrativeUnits::ResidenceOfAuthority data type is converted to a feature class in the geodatabase, even if instances of the data type conceptually do not have an identity and are just values owned by the parent spatial object type.
Most INSPIRE application schemas use generalization relationships between spatial object types. Geodatabases do not support generalization as used in UML models. However, they support the subtype concept that has some similarities and is used for converting generalizations to the INSPIRE geodatabase. The root class of an inheritance tree is converted to feature and/or object classes and all properties of their subtypes are converted to fields of them. An additional STYPE field distinguishes the type of each instance. The STYPE field must be set for all such instances. Depending on the instance, only the applicable fields are relevant.
The INSPIRE Hydro - Physical Waters::DrainageBasin spatial object type and the Hydro - Physical Waters::RiverBasin subtype are both converted to the hypBasinS feature class.
In some cases, the INSPIRE application schemas use multiple inheritance. In these cases, the properties from the abstract supertypes are propagated to all subtypes.
The hydroId, geographicalName, and relatedHydroObject properties from the HydroObject are represented in the feature classes of all subtypes, for example, DrainageBasin (hypBasinS).
The associations between INSPIRE spatial object types depends on the multiplicity of the relationship. For 1:n relationships a field with a foreign key reference is added directly in the feature or object class. An intermediate table (object class) is created for n:m relationships. The relationship class capability of geodatabases is not used to improve performance, in particular during data loading. In addition, geodatabases do not support relationship classes for reflexive associations. The relationship is accessible in ArcMap via other mechanisms.
The 1:n relationship upperLevelUnit/lowerLevelUnit between instances of AdministrativeUnits::AdministrativeUnit is converted to the upperLevelUnit field.
The n:m relationship coAdminister/administeredBy between instances of AdministrativeUnits::AdministrativeUnit is converted to the auAdmUnit_admBySS intermediate table.
Additional notes and default values
The INSPIRE geodatabase template is based on the following:
- The coordinate reference system is EPSG:4258.
- In the conversion process, it may be advisable to apply dataset-dependent rules. A specific case is the mapping of the data type GeographicalNames::GeographicalName. The INSPIRE data specification points out that different profiles may be used depending on the requirements. The complete data type contains a comprehensive model that is only relevant for a few datasets. In most datasets a significantly reduced model is sufficient—converting a geographical name to a string. By default, the geodatabase is configured for the easiest profile. For cases where a complex model for geographical names is required, for example, representing a name in multiple languages and scripts (for example, Athen, Athens, Athína, and Αθήνα), a configuration option is available for enabling the full GN profile for NamedPlaces.
- All geometries are limited to linear interpolation including the theme Cadastral Parcels, which allows the use of circular arc interpolation.
- The geodatabase contains by default all INSPIRE application schemas (with the exception of the unused gazetteer schema), even if only selected application schemas are needed.
- For properties, where values are structured types from ISO 19115, for example, CI_Citation, the value has to be stored in ISO/TS 19139 XML directly in the geodatabase field. This implies that no structured queries are supported on these attribute values.
- The property relatedHydroObject in all spatial objects that inherit from HydroObject is converted using a special rule. The standard rule would have led to an inappropriate number of intermediate tables for relationships in the geodatabase. The property is converted to a field that must contain the URI of the referenced spatial object instead of the IFCID of the object.
Documentation of the feature and object classes in the INSPIRE geodatabase for Annex I
The complete description of the INSPIRE geodatabase is provided as a collection of linked documents that may be viewed in a web browser. This is available in the INSPIRE installation folder under the GDB Templates folder.
For each feature or object class associated with an INSPIRE spatial object type, a separate XML document is provided. In large parts, the documentation is taken directly from the documentation in the INSPIRE application schemas. Each document contains the following:
- Index to the sections of the document with links to them
- List and documentation of the INSPIRE spatial object types that are converted to the feature or object class; this includes the subtype codes (STYPE field)
- Fields of the feature or object class with the name of the field, the name of the source property in the INSPIRE application schema, the list of INSPIRE spatial object types for which this field applies, the data type in the geodatabase, and the documentation of the property with additional remarks about the conversion into the geodatabase
- Dependent feature or object classes (to represent additional geometry properties or multiple attribute values) with documentation and the list of all associated fields
- Intermediate tables of the n:m relationships
Notes for Annex II/III data theme
The following are the Annex II/III specific geodatabase implementation guidelines. These are Annex II/III specific and take precedence over Annex I rules:
- Feature classes belong to a particular data theme are organized inside a feature dataset for that data theme. This supports better navigation and expansion when many additional data themes for Annex II/III are implemented.
Annex II/III Geology and Land Cover feature class and table don't use the IFCID as the unique identifier as in Annex I. Instead, each tables has its own unique identifier and:
- In the Geology data theme, featureID is used by multiple tables, and has to be unique not just within the table but also in the data theme.
- In the Geology data theme, mappedFeatureID and boreholeID together is used by multiple feature classes, and has to be unique not just within the feature class but also unique in the geology data theme.
- In Annex II/III, geodatabase relationship class is used to model the relationship between feature classes and tables to leverage geodatabase relationships. In most case, the same identifier name is used for primary key and foreign key references.
- _void fields are populated through the use of the geodatabase domain VoidReasonValue in Annex II/III.
- Due to the fact that many of the code list values in AnnexII/III are dynamic, expandable, and unknown ahead of time, in most cases, in the geodatabase INSPIRE code list for Annex II/III are implemented through following three fields:
- _code—Contains the code used for the codelist
- _label—Contains the label used for the codelist value
_uri—Contains the URI reference for the codelist value
- Some of the attribute data with unbounded multiplicity defined in INSPIRE spatial objects has been flattened in the geodatabase structure to make data population, performance, and presentation easier.
- Documentation for each Annex II/III data themes include a data model diagram and a data dictionary document that is available in the INSPIRE installation folder under the GDB Templates folder.