Assignment 3: Alignment TGN-GeoNames

Assignment Type:

Research Report, 4 pages max.

Assignment:

Aligning ontologies is one of most important tasks in practical ontology engineering. We cannot enforce one view of the world, even in restricted domains such as geographical information. Instead we can try to “align” ontologies: specifying a set of semantic relations between ontologies (see the lecture). Such semantic relations are typically incomplete. The objective of this assignment is to get some practical experience with ontology alignment.

Two geographical vocabularies:

TGN

The Thesaurus of Geographic Names (TGN) represents a large information repository about places on earth. It is constructed as a big part-of structure with World as the top node of the hierarchy.

Full technical information about the data model of TGN can be found at the download page of the three Getty thesauri. Sample data and the data model are available in XML and relation-table format. This information is not easy to read (but this is typical of most real-life situations). To make the assignment easier, a simplified annotated data model of TGN is included in the appendix below. This data model also shows the scope that the OWL specification should cover. More background information on the TGN can be found at the Getty website, but be aware that the scope of the documentation there is broader.

Geonames

Geonames is a large geographical vocabulary which is available in various formats, including RDF. The data model of Geonames can be derived fromhttp://www.geonames.org/ontology/ontology_v2.0_Lite.rdf and example records such as:

• the river Danube http://sws.geonames.org/791630/about.rdf
• Delft (populated place) http://sws.geonames.org/2757345/about.rdf, with parent features:
  • Gemeente Delft: http://sws.geonames.org/2757344/about.rdf
    • Provincie Zuid Holland http://sws.geonames.org/2743698/about.rdf
      • Kingdom of the Netherlands http://sws.geonames.org/2750405/about.rdf

Assignment tasks:

1. Study the information about the two vocabularies and construct/assemble two OWL models of the following information:
   • places, place names, place types
   • geographical positions
   • part-of hierarchy(ies) of places
   • other inter-place relations, if any

   NOTE1: Concentrate the main geographical information in the vocabularies. You don’t have to model all the information in the vocabulary, only what is represented in Appendix A.

   NOTE2: Focus on modeling the data model (i.e the information represented in Appendix A). You can add a few instances (e.g. Paris is part of Something) for clarity.

2. Describe possible alignments between the two vocabularies on the “class” level. Indicate which information is present in one vocabulary and not in the other. Construct an OWL specification of the alignments you identified. Provide adequate explanatory text for the major decisions.
3. Describe possible alignments between the two vocabularies on the “property” level. Indicate which information is present in one vocabulary and not in the other. Construct an OWL specification of the alignments you identified. Provide adequate explanatory text for the major decisions.
4. Literature Question:
   Discuss alignment at the instance level: how can we establish that two particular place (e.g., two “Paris” instances) are the same? How precise do you think an automatic instance-alignment technique would be?

Hints and tips:

• Think carefully about the nature of the part-whole hierarchies in the two vocabularies; consult the course information about such relationships.
• If you lack adequate information about the meaning of a particular construct, it is OK to make an “educated guess”:;motivate why you took a particular view and document the decision in the accompanying text document.
• It is is OK if you propose more appropriate names, but record this explicitly as a modeling decision.

Target Results:

A PDF file containing:

• OWL specification of TGN and Geonames.
• OWL specification of mappings between classes.
• OWL specification of mappings between properties.
• Text with explanation of the above three steps.
• Text with discussion of the literature question.

The OWL specifications can be send as files or as links.

Submission deadline:

Monday 26 November, 23:59 CET

Appendix A: Simplified data model of TGN:

This appendix contains a simplified data model of TGN, covering the part of TGN that is within the scope of this assignment. The record structure is a simplified form of the original record structure. We use the following conventions in describing the record structure:

   []       optional element
    {}*   list of 0-n elements
    {}+   list of 1-n elements
    ->;       points to another record
    :       datatype of the element

TGN consists of a large collection of Subject (records each representing information about a particular place:

• Each place has a unique ID and a textual description with background information about the place.
• TGN uses the “Parent” relationship to represent a part-whole hierarchy. In fact, there are two of such hierarchies, one topological hierarchy between physical places and a nation/town-based hierarchy between administrative places. Some places only occur in the administrative or topological hierarchy, (e.g. North-Holland is administrative, the Mont Blanc is physical), other places can be both (e.g. Europe).
• Each place has a preferred term for referring to it (e.g. “Gorinchem”) and possibly alternative term (e.g. “Gorkum”).
• Each place has at least one PlaceType, such as Nation or River.
• Places can also be associated to other places. TGN has a possibility to type this relation, but you can omit this for the assignment.

 Subject
    SubjectID : integer minInclusive 1000000 maxInclusive 699999999
    DescriptiveNote : string
    PreferredParent ->; Subject
    {NonPreferredParent}* ->; Subject
    RecordType: {Administrative Physical Both}
    PreferredTerm ->; Term
    {NonPreferredTerm}* ->; Term
    PreferredPlaceType ->; PlaceType
    {NonPreferredPlaceType}* ->; PlaceType
    {AssociativeRelation}* ->; Subject
    StandardCoordinates ->; StandardCoordinates
    [BoundedCoordinates] ->; BoundedCoordinates

For each place there can be multiple terms to refer to it. TGN keeps information about both the terms used nowadays (Current) and previously-used terms. For the latter a start/end date can be recorded. Both noun terms (“Europe”) as well as adjective terms (“European”) are provided by TGN. The attribute Vernacular indicates whether this is a term from the native language of the place (e.g. “Den Haag” is vernacular; “The Hague” is not).

 Term
    TermId : integer
    TermText : string
    TermType : {Noun Adjectival Both}
    HistoricFlag : {Current Historical}
    Language : ISO language code
    [StartDate] : year
    [EndDate] : year
    Vernacular: yes/no

Place types are ordered in a taxonomy:

 PlaceType
    Parent ->; PlaceType

For each place standard coordinates are indicated, such as latitude and longitude. Optionally (see the Subject record structure), information about the bounding coordinates is provided:

 Standardcoordinates
    SatndardLatitude : decimal
    StandardLongitude : decimal
    [ElevationMeters] : decimal

BoundedCoordinates
BoundingLatitudeLeast : decimal
BoundingLatitudeMost : decimal
BoundingLongitudeLeast : decimal
BoundingLongitudeMost : decimal