Now we build upon that work to develop a vocabulary of Classes and their Properties for describing government service.
Seeding the Vocabulary
The starting point for seeding our vocabulary is Schema.org’s Class GovernmentService, used to describe a service that is provided by a government organization or by an organization that is funded by government.
Figure 1 illustrates the pathway to Class GovernmentService within Schema.org’s Inheritance Hierarchy.
Figure 1. Pathway to GovernmentService through Schema.org.
Class GovernmentService has one Property – serviceOperator – that is expected to be of Type Organization – another Class in Schema.org. GovernmentService is the Domain of serviceOperator and Organization is its Range.
Schema.org’s website represents the above in the form of a Table:
|Properties from GovernmentService|
|serviceOperator||Organization||The operating organization, if different from the provider. This enables the representation of services that are provided by an organization, but operated by another organization like a subcontractor.|
Table 1. Properties of Class GovernmentService.
We may also represent the information in Table 1 as a Graph, where the Nodes are Classes and Properties, and where the Links are relations connecting them:
|Source Node||Target Node||Link|
Table 2. Graph of vocabulary for describing service that is provided by a government organization.
Extending the Vocabulary – Cycle 1
This start on a vocabulary for describing government service may be extended in a systematic fashion – first, by incorporating any SuperClass (and its Properties) that contains GovernmentService as a Subclass.
In this manner, our vocabulary extends to include Class Service, Intangible, and Thing – as well as their respective Properties. (Note that these Classes are the points highlighted along the pathway in Figure 1).
Again, Schema.org’s website represents each of these SuperClasses in the form of a Table:
|Properties from Service|
|availableChannel||ServiceChannel||A means of accessing the service (e.g. a phone bank, a web site, a location, etc.)|
|produces||Thing||The tangible thing generated by the service, e.g. a passport, permit, etc.|
|The service provider, service operator, or service performer; the goods producer. Another party (a seller) may offer those services or goods on behalf of the provider. A provider may also serve as the seller.|
|serviceArea||AdministrativeArea||The geographic area where the service is provided.|
||Audience||The audience eligible for this service.|
|serviceType||Text||The type of service being offered, e.g. veterans’ benefits, emergency relief, etc.|
Table 3.1. Properties of Class GovernmentService that are inherited from Class Service.
|Properties from Thing|
|additionalType||URL||An additional type for the item, typically used for adding more specific types from external vocabularies in microdata syntax. This is a relationship between something and a class that the thing is in. In RDFa syntax, it is better to use the native RDFa syntax – the ‘typeof’ attribute – for multiple types. Schema.org tools may have only weaker understanding of extra types, in particular those defined externally.|
|alternateName||Text||An alias for the item.|
|description||Text||A short description of the item.|
|An image of the item. This can be a URL or a fully described ImageObject.|
||Text||The name of the item.|
|potentialAction||Action||Indicates a potential Action, which describes an idealized action in which this thing would play an ‘object’ role.|
||URL||URL of a reference Web page that unambiguously indicates the item’s identity. E.g. the URL of the item’s Wikipedia page, Freebase page, or official website.|
|url||URL||URL of the item.|
Table 3.2. Properties of Class GovernmentService that are inherited from Class Thing.
Class Intangible has no Properties of its own – all of its Properties are inherited from Class Thing.
At the end of Cycle 1 of extending the vocabulary, our Graph is looking much more respectable (compared to Table 1):
At the end of Cycle 1 of extending the vocabulary, our Graph has become much richer (compared to Table 1):
|Source Node||Target Node||Relation|
Table 4. Graph of vocabulary for describing service that is provided by a government organization (Cycle 1).
Note in Table 4 that Property image may be of type URL or ImageObject; here we’re going to use only “cool” URLs – both for the sake of having a persistent identifier for an image that may be modified from time to time and to avoid introducing the clutter of a complex entity like ImageObject – which is incidental to the semantics of a government service – into our vocabulary.
Also note in Table 4 that Property provider may be of type Organization or Person; here we’re going to restrict ourselves to providers of government service that are organizations and not individuals. We will bring Class Person (e.g. as an employee of an organization) into our vocabulary in a subsequent Cycle.
In a fairly traditional manner, our vocabulary for GovernmentService may be visualized as a basic Class Diagram using the Unified Modeling Language (UML):
Figure 2. Visualization of Vocabulary for GovernmentService (Cycle 1) using a UML Class Diagram.
In a more innovative fashion, we may also visualize our vocabulary GovernmentService as a Force-Directed Graph (with Thing, Intangible, Service and GovernmentService fixed in position in the corners of the graph:
Figure 3. Visualization of Graph of GovernmentService (Cycle 1), where o = Property, D = Domain, and R = Range.
See also this interactive version of Figure 3.
Note in Table 4 that several Properties are of type Text or URL – Schema.org treats Text, URL and a few other entities (Boolean, Date, DateTime, Number, Time) as a Datatype (as opposed to a Thing). We may streamline the visualization of our vocabulary by terminating any node corresponding to one of these Properties with a colored-symbol specific to its Datatype:
Figure 4. Legend for terminating a Property node whose Range is Datatype.
Here’s our streamlined visualization of our vocabulary for GovernmentService:
Figure 5. Visualization of Graph of GovernmentService (Cycle 1) using D3, where o = Property, D = Domain, and R = Range, terminating Property nodes with Range = Datatype.
See also this interactive version of Figure 5.
Coming Up:A Vocabulary of Government Service – Part II
Part III: The Architecture of Service: the Service Organization and Service Channel
Part IV: The Service Audience and Administrative Area
Part V: The Service Action