Global Positioning System Reference
In-Depth Information
as back-end and the databases supported by SDB are not available in
smartphone OS. Thus, SDB cannot be used as a triplestore for Androjena.
There is also a project called android-sparql (Sesame 2012) developed
for Android OS, which is an extension of OpenRDF. It can be used to create
and populate a triplestore on an Android device, as well as a web application
with a simple implementation of the SPARQL protocol. Even though it is
possible to store data on a triplestore in the device, SPARQL queries require
Internet connection to perform the queries over the triplestore. Thus, it is not
useful for the application we are looking for, because it does not accomplish
the requirement of working offl ine.
Finally, there is the MobileRDF (Hedenus 2008) open source project.
It is a lightweight implementation of RDF developed for Java ME that
offers a simple and easy-to-use API. It has simple functionalities like
RDF parsing and serialization. Java ME is a Java platform designed for
embedded systems, thus MobileRDF could be used as a library in an
Android application. The main drawback is that MobileRDF does not offer
inference or more complex RDF tasks.
Integration of Semantic Web in GIS
Summarizing, the building blocks of Semantic Web are: 1) semantic data,
which is represented as triplets in the standard model, called RDF; 2)
ontologies, which contains information about the domains of interest by
representing the related data, relationships between data, domain constraints
and inference rules; 3) reasoners that provide functions to infer new
knowledge via inference and validate RDF instanced data via ontologies;
and 4) query language, that allows to retrieve data from ontologies.
Therefore, using geographic ontologies and frameworks able to reason
over RDF spatial data, we can integrate GIS and Semantic Web functionalities.
However, current state of the art of GIS does not support completely
semantics (Van Hage et al. 2010). Thus, the integration between semantic
and spatial context is a current focus of study nowadays (Descamps-Vila
et al. 2012a; Hoekstra et al. 2010; Van Hage et al. 2010). On the other hand,
several initiatives are working to incorporate Semantic Web that is an
important research focus (see for example, Ordnance Survey 2013).
The use of semantic data together with geographic functions in
smartphones would allow, for example, creating tourism guides like the
mobile cultural guide of Van Aart et al. (2010), developing systems to create
and share tourism information like CsxPOI (Max 2009); creating urban
computing demonstrators, such as the one of Milano city (Della Valle et al.
2010), or prototypes of DBPedia mobile (Becker and Bizer 2012). Currently,
the drawback of all these applications is they use a server to perform
semantic operations.
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