Architecture for Including Personalization in a Mobile GIS via Semantic Web Techniques - Geographical Information Systems: Trends and Technologies - page 215

For example, in the particular case of a tourism system, the basic
concepts of a city should be described. From an ontology point of view,
every one of these concepts is a class. Figure 1 shows part of an ontology
used for a tourism domain. The classes of the ontology could be a Point
of interest , a Resource , a Spatial point , etc. Classes may also be specialized
using subclasses. For instance, a subclass of Point of interest class could be
a Historic point and a subclass of the Historic point could be a Monument
(represented in orange color in Fig. 1). On the other hand, an instance of
Monument class may be SagradaFamilia and an instance of Resource class
may be a picture: Photo (represented in purple color in Fig. 1). An Object
Property hasResource , allows to link the SagradaFamilia instance with the
Photo instance, indicating what is shown in the picture. Then, the name is a
data property that is used to relate the SagradaFamilia instance with a String
value that indicates the name of the monument.

Historic
superclasses :

Historic

Historic SubClassOf PointOfInterest

Resource

Monument
superclasses :

Monument

Monument SubClassOf Historic

SagradaFamilia
Object property assertions :
SagradaFamilia hasResource Photo
Data property assertions:

Photo

SagradaFamilia

SagradaFamilia name “La Sagrada Familia”^^string

Fig. 1. Fragment of an ontology used for a tourism domain.

Color image of this figure appears in the color plate section at the end of the topic.

SPARQL

Data that represents ontology information of Fig. 1 is stored in RDF triplets
within a triplestore, which is a specifi c database built for the storage and
retrieval of triples. Since in a relational database, triplestores can be queried
by using a query language, which is called SPARQL (W3C 2012). SPARQL
is the equivalent of SQL in relational databases, but limited to query
operations. As an example, the following lines show a SPARQL query over
the ontology of Fig. 1.

PREFIX owl: <http://www.w3.org/2002/07/owl#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>