IMX-Geo

The information model should be user-friendly, i.e.:

• Simplified structures for common use cases, like the Address class
• Names that correspond with common language, e.g. straatnaam instead of Openbare ruimte naam.

It should be possible to leave out properties, that are present in the source model but not of interest to the users.

The semantic model should be user-friendly as well. In this case that means developers should be able to read the model easily to discover the paths leading to the information they want.

The SAM information model should add useful relationships that exist inherently between objects, but are not currently defined in the source models.

Background: because the source models were originally defined as silos, relationships between objects from different source registries are mostly unavailable right now. We have a requirement to add those relationships that are of value to users (definitely not all).

The added relationships between SAM and source models cannot change the source object types as this goes against maintenance and ownership principles. The additional relationships must be added in a separate semantic layer.

The SAM information model should not be completely independent / a completely new model, but should be linked to the source models.

The SAM model will re-use classes and properties from source models, and derive information from source models. SAM classes and properties should contain information about the source they depend on.

The links between objects/properties in the SAM model and objects/properties in source models should be machine readable. This opens up possibilities to automate things for the knowledge graph and the orchestration.

It should be possible to keep the SAM information model in sync / up to date with the source models without too much effort / impact.

When changes in source models are published and implemented in data sources, the SAM information model should be updated to take those changes into account.

Note that base registry models do not change at all frequently.

• 2.1 User-friendliness - the model introduces classes that correspond to the common point of view of users. Mappings can be used to add user-friendly names for things. These names will also be added in SKOS (MIM level 1).
• 2.2 Cherry-picking - the model is loosely coupled to the source classes and requires a mapping for each source class.
• 2.3 Aid data discovery - the model shows how classes are related, including cross-registry relationships.
• 2.4 Coherence between objects from different source models - the model introduces relationships between objects from different sources
• 2.5 Coherence in extra layer - the model is loosely coupled to the source models using mappings.
• 2.6 Link with source models - the model does contain links to the source classes to indicate which data is derived from which source class.
• 2.7 Machine readability - the model is expressed in SKOS and MIM. MIM can be expressed UML but also in XML and RDF.
• 2.8 Maintainability - the model is loosely coupled so changes in the source models do not directly impact it, unless changes include the addition or removal of classes. Mappings can be impacted by changes in properties, but the mappings are maintained outside of the model.

The concept scheme is a MIM level 1 model and introduces user-friendly concepts to talk about the universe of discourse.

URI: https://begrippen.geostandaarden.nl/sm/nl/.

sm stands for 'samenhangende begrippen' which is 'coherent concepts' in English.

Design principles:

• The concept scheme is created in SKOS [skos-reference].
• The concept scheme contains only those concepts that play a role in the IMX-Geo universe of discourse but have not been coined elsewhere in the context of the Dutch base registries. I.e.: we only coin those concepts that do NOT have an exact match with an existing concept (again, in the context of the Dutch base registries). This saves work and maintenance. We will find out if this is workable.
• We create the concept scheme manually, we do not generate it from a UML model. The reason is that we want to be able to link related concepts in ways not supported in UML (see next point).
• Concepts will have matching relationships (broadMatch, narrowMatch, closeMatch, relatedMatch) with existing concepts from the Dutch base registries where appropriate. Note: exactMatch is excluded (see point 2).
• Both the conceptual and the logical model have annotations containing the uris of concepts from a Dutch base registry or from the IMX-Geo sm concept scheme. These are entered in the MIM metaproperty begrip. Every class and property has this metadata.

The work-in-progress version of the concept scheme can be viewed here.

In this section, we list a set of design principles, and describe a first modeling attempt. After creating a first attempt at a conceptual model, we decided to focus on the logical level first, in order to see how it can play a role in the orchestration engine. We retain the old design principles and modeling attempt for now - they may or may not still be valid.

Conceptual modeling principles:

1. The conceptual model will be a valid UML [MIM11] model on MIM level 2, with the exception that we may define extensions of MIM if we need them.
2. The conceptual model defines the classes of our universe of discourse (see scope). It identifies the object types and their inherent properties, including relationships with other objects.
3. The conceptual model describes how the classes in our universe of discourse relate to each other. These relationships can cross the boundaries of individual base registries.
4. We relate all object types and properties to corresponding SKOS concepts as described in the previous section.
5. In this conceptual model we will define relationships between objects if they are relevant for users, even though they may not be present in the source datasets (which were designed as silos).
6. We model the relationships between object types in different source registries by adding these to the copied classes. More on these last two points below.

This preliminary, partial sketch of the conceptual model contains a few object types from BAG, BRK, and DiSGeo. It is only a sketch of how object types from different base registries could be related.

An assumption is that we have access to the information models for all source datasets. These are created using modeling language UML.

The logical model defines the shapes of the data. On this level we add data-registration concepts like history and provenance. The logical model also specifies how orchestrated data is related to source data, at least on the class level.

This logical model must satisfy all requirements in 2. Requirements. I.e we want to be able to add relationships, without changing source models, but retain a link TO source model classes we derive information from; in a machine readable way, but also usable for developers to discover the available information and how it can be integrated. The maintenance requirement is less important, because the source models do not change often, once standardized.

We are planning to introduce a generic modeling pattern on the MIM level (i.e., in the metamodel) for provenance that can be applied to describe how orchestrated data was created from source data. A first version of this was created as part of our first use case, Adresses. This provenance or lineage information will also be available to users on request. The Lineage model is developed separately in the IMX-LineageModel repository.

This is the current attempt at creating the cross-domain model on the logical level:

Cluster classes are classes we add in the model. In the example above, Gebouw and Perceel are cluster classes. Cluster classes represent a logical unit of information about a real-world object, in which data from different source models can be integrated. They are not present in a source model, but are related to one or more classes in source models. They always have a MIM Begrip metadata field containing the URI of either a concept in a source model, or a concept coined in the context of IMX-Geo.

Trace links: Links between cluster classes and source classes are expressed using UML <<trace>> relationships. They indicate that the cluster class is derived from these source classes - one at minimun, but since we are integrating data from different sources there will often be several trace links originating from one cluster class. Every <<trace>> relationship indicates that data is retrieved from a certain source class, and that a mapping is needed to specify how this is done. The mapping is maintained outside of the model.

Generalization: In an earlier stage of our thinking, we wanted to use <<generalization>> relationships between a cluster class and a source class in cases where the cluster class only has one related source class, and the wanted behaviour is to copy all properties from the source object, and to add one or more properties.

However, during the second High 5 we discussed this and concluded that these cases would probably be few, and this approach also had the disadvantage of linking the cluster classes more tightly to the source classes. When using generalisation, IMX-Geo effectively becomes an extension of the source models, while we want to specify IMX-Geo as a separate layer which is only loosely coupled. Therefore, we decided to use only trace relationships.

Associations: Whenever we want to introduce a relationship to cross-link two classes from different source models, we add this relationship between the corresponding cluster classes.

The IMX-Geo model introduces several spatial relationships between object types. We want to model these according to the Simple Features topological relationships (also included in NEN 3610 and GeoSPARQL), so we have to consider for each of these relationships, which topological relationship is the correct one.

To understand the topological relationships we looked at DE-9DIM on wikipedia:

• Contains: a geometry contains another geometry. There are no points of the contained geometry that lie outside the boundary of the containing geometry.
• Overlaps: two overlapping geometries have some points in common, and have the same dimension; their intersection also has the same dimension.
• Intersects is very broad: two geometries have at least one point in common.
• Touches: two geometries have at least one point in common, but the interiors do not intersect.

The IMX-Geo currently has these spatial relationships:

• ligtInGemeentegebied: Perceel objects within a Gemeentegebied. They never overlap.
• gebouwBinnenKlicMelding: Gebouw objects within a Klicmelding area, or having overlap with it.
• adresBinnenKlicMelding Adres objects within a Klicmelding area, or having overlap with it.
• bevatBouwwerk: Perceel objects or Terrein objects that contain a Bouwwerk or have Bouwwerk objects that overlap with it.
• ligtInWaterschap: Perceel objects that are within a Waterschapsgebied.
• heeftBestemming: Perceel objects that are within a Bestemming or overlap with it.
• Terrein bevat: Terrein objects that contain Landschapselement objects.
• heeftAlsOndergrondOnderTerrein: Terrein objects that contain or have overlap with Ondergrond objects.
• heeftAlsNabijWater: Terrein objects that are nearby Water objects. However, there is no GeoSPARQL relation that has this meaning. As far as I know only http://www.geonames.org/ontology#nearby expresses this.
• heeftBestemming: Perceel objects that contain or have overlap with Bestemming objects.
• heeftBeperking: Probably not a spatial relationship. Todo check.
• RegistratieveRuimte bevat: Registratieve ruimte objects (subclasses) that contain Perceel objects.
• ligtAan: Adres objects that touch a Weg object? I am not sure this is what is meant.

This section lists the properties contained in IMX-Geo that are mapped to external, standardized properties. This mapping is present in the IMX-Geo model. A tagged value uri is used for this.

Generic mapping of properties that occur in different classes:

• geometrie: geosparql:hasGeometry
• identificatie: nen3610:identificatie
• domein: nen3610:domein
• ligtOp/ligtIn/binnen geosparql:sfWithin or geosparql:sfIntersects (see previous section)
• bevat: geosparql:sfContains or geosparql:sfIntersects
• naam: rdfs:label

Specific mapping of properties of certain classes:

• Terrein bevat Landschapselement: geosparql:sfContains
• Terrein bevatBouwwerk Bouwwerk: geosparql:Intersects
• Bestemming: verwijzingNaarArtikel: dct:source
• Perceel heeftBestemming Bestemming: assuming this will be implemented as a spatial relationship, geosparql:Intersects
• Perceel bevatBouwwerk Bouwwerk: geosparql:Intersects
• RegistratieveRuimte bevat Perceel: geosparql:sfContains
• Perceel oppervlak: geosparql:hasMetricArea (geosparql 1.1)
• Perceel koopjaar: owl-time:year

Other properties besides those mentioned above are not mapped to external standardized properties.

The Stelselcatalogus provides insight into the Dutch base registries / governmental data.

It is a collection of concepts that describe the governmental data that exists within the different base registries. It also contains a short list of "cluster concepts", concepts that were added to serve as entry points to the more detailed base registry concepts.

As part of the analysis, we compared the classes in IMX-Geo to the cluster concepts in the Stelselcatalogus.

Adres, Bouwwerk, Ondergrond, Terrein, Water, and Weg match Cluster concepts pretty closely.

Aansprakelijkheid, Inkomen, Locatie, Natuurlijk persoon, Omzet, Organisatie, Roerende zaak, and Vestiging are Cluster concepts that don't match any class in IMX-Geo. This is okay; most of them are not in scope for IMX-Geo, because they are not about spatial objects.

The Cluster concept Locatie is too generic to use in IMX-Geo; everything has location in IMX-Geo so it doesn't make sense to have this class there.

Perceel in IMX-Geo falls under the Cluster concept Onroerende zaak. For now, we only need Perceel, not the other subclasses of Onroerende Zaak (Appartementsrecht and Leidingnetwerk) but it might be interesting to add those later. If that's the case, it would be better to add the Onroerende Zaak class to IMX-Geo instead.

IMX-Geo has quite a few concepts that don't match a Cluster concept. Several of these classes are a bit more specific than the Cluster concepts are, so it makes sense the are missing from the Cluster concepts in the Stelselcatalogus. Others, like Bestemming, are not in scope for the stelselcatalogus, because the data for these things is not in a base registry.

For Bestuurlijk gebied it could be argued that it should be a Cluster concept - or its superclass in NEN 3610, Registratieve ruimte. Gemeentegebied and Waterschapsgebied would fall under this as well. Gemeente and Waterschap are subclasses of Openbaar Lichaam (introduced in DisGeo but also in TOOI); this could also be a Cluster concept as there is government data about these governmental organisations.

We looked at Kadaster Knowledge Graph (KKG) use cases that were assembled in earlier projects, as well as questions about datasets posed by users at the Geoforum. Approximately 50% of these use cases was covered by IMX-Geo (at analysis time, during the fourth high5 in May 2023).

Some highlights of this analysis:

• Many questions used neighbourhoods (wijken/buurten)

• A number of use cases needed data which is within scope of IMX-Geo, but was not yet included in the model: e.g. trees, wells, statusses, swimming pools, sports halls, terrain functions, playground equipment, publiekrechtelijke beperkingen.

• A number of use cases needed data that was out of scope of IMX-Geo, such as risk objects, CBS kerncijfers, floor height.

As a result of this, Neighbourhood (buurt/wijk) was added as well as Publiekrechtelijke beperking.

Details of this analysis are in this spreadsheet.

We have had discussions with information model managers to retrieve use cases of integrated use of geo-basic data.

The following conversations took place:

• 17.05.2023: BGT & DiS-Geo

• 26.05.2023: BAG

• 30.05.2023: BRO

• 31.05.2023: KLIC / IMKL

• 01.06.2023: BRK

• 08.05.2023: Ruimtelijke Plannen / IMRO

As a result of these conversations, we collected 21 use cases:

1. Heat stress or flooding

2. Locations of windmills at sea

3. Where was I born?

4. Urban or rural area

5. Access to inheritances

6. Street width for loading/unloading

7. NL Alerts in the event of smoke development

8. Risk of flooding

9. Housing typing

10. Number of floors and entrance door

11. Energy labels

12. Home insulation, asbestos remediation and lead water pipes

13. Policy on housing (re)construction and vital neighbourhoods

14. Repressive object information

15. Influence of mining on the built environment

16. Salinization

17. Residential building locations

18. Realistic housing offer

19. Environmental label for houses

20. Digging area information

21. Drone locations

Details of this analysis are in this spreadsheet.

Finally, we compared the IMX-Geo model to the source models that are within scope, to find any other classes we wanted to support.

When developing the IMX-Geo, we chose to only add those objects to the model that are relevant to a certain use case. The IMX-Geo therefore only contains those objects that are mentioned in a use case.

As a result of this, the IMX-Geo now contains 60% of all objects/concepts that appear in the source models. See table below.

BAG and BGT are almost fully supported. Because KLIC is recognized as a consumer of data by means of the IMX-Geo, IMKL is not part of IMX-Geo anymore.

The IMX-Geo can grow over time and support more objects/concepts from source models as the IMX-Geo is expanded based on new use cases, hitting new objects.

Details of this analysis are in this spreadsheet.