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| Titel |
Browsing and Visualization of Linked Environmental Data |
| VerfasserIn |
Charalampos Nikolaou, Kostis Kyzirakos, Konstantina Bereta, Kallirroi Dogani, Manolis Koubarakis |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250092920
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| Publikation (Nr.) |
 EGU/EGU2014-7285.pdf |
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| Zusammenfassung |
| Linked environmental data has started to appear on the Web as environmental
researchers make use of technologies such as ontologies, RDF, and SPARQL. Many
of these datasets have an important geospatial and temporal dimension. The
same is true also for the Web of data that is being rapidly populated not only
with geospatial information, but also with temporal information. As the
real-world entities represented in linked geospatial datasets evolve over
time, the datasets themselves get updated and both the spatial and the
temporal dimension of data become significant for users. For example, in the
Earth Observation and Environment domains, data is constantly produced by
satellite sensors and is associated with metadata containing, among others,
temporal attributes, such as the time that an image was acquired. In addition,
the acquisitions are considered to be valid for specific periods of time, for
example until they get updated by new acquisitions. Satellite acquisitions
might be utilized in applications such as the CORINE Land Cover programme
operated by the European Environment Agency that makes available as a
cartographic product the land cover of European areas. Periodically CORINE
publishes the changes in the land cover of these areas in the form of
changesets.
Tools for exploiting the abundance of geospatial information have also
started to emerge. However, these tools are designed for browsing a single
data source, while in addition they cannot represent the temporal dimension.
This is for two reasons: a) the lack of an implementation of a data model and
a query language with temporal features covering the various semantics
associated with the representation of time (e.g., valid and user-defined), and
b) the lack of a standard temporal extension of RDF that would allow
practitioners to utilize when publishing RDF data.
Recently, we presented the temporal features of
the data model stRDF, the query language stSPARQL, and their implementation in
the geospatial RDF store Strabon (http://www.strabon.di.uoa.gr/)
which, apart from querying
geospatial information, can also be used to query both the valid time of a
triple and user-defined time.
With the aim of
filling the aforementioned gaps and going beyond data exploration to map
creation and sharing, we have designed and developed SexTant (http://sextant.di.uoa.gr/).
SexTant can be used to
produce thematic maps by layering spatiotemporal information which exists in a
number of data sources ranging from standard SPARQL endpoints, to SPARQL
endpoints following the standard GeoSPARQL defined by the Open Geospatial
Consortium (OGC) for the modelling and querying of geospatial information, and
other well-adopted geospatial file formats, such as KML and GeoJSON.
In this work, we pick some real use cases from the environment domain
to showcase the usefulness of SexTant to the environmental studies of a domain
expert by presenting its browsing and visualization capabilities using a
number of environmental datasets that we have published as linked data and
also other geospatial data sources publicly available on the Web, such as
KML files. |
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