Geoscience Reference
In-Depth Information
Illustrating example:
Let us consider the example on
figure 2
,
and
suppose that the user wants to know where and how are represented basins
in the databases annotated with this ontology. From the free text '
basins
'
filled by the user, the system proposes him/her the term '
Basin
' included in
the topographic domain ontology. Next, the system retrieves all classes of
the local specification ontologies which are annotated with the concept of
basin, such as the class '
Other_water_point
', among others. After that, the
system retrieves data from the table '
Other_water_point
' of the database,
where basins are stored, and sends them to the user as well as other
information from the local specification ontology such as the type of
geometry of the data (here basins are stored with points in the database),
and the capture constraints on basins (here the database includes only
basins that are longer than 10 meters). Finally, a web mapping solution
allows the user to visualize capture constraints and available data
themselves, in order to evaluate if they fit to his/her needs. This may be
simultaneously done for several datasets, and thus enables a precise
comparison of specific interests of each dataset.
3- System implementation
The proposed system is a web application allowing serving a large number
of users (
Figure 4
). A prototype has been implemented using two
specification ontologies associated with two IGN databases (
BDTOPO
®
and
BDCARTO
®). These ontologies are represented in
OWL 2
and are
actually restricted to the hydrographic theme. Programs running on the
server are implemented in
Java
, using the
OWL 2 API
6
for parsing
ontologies. For the web side,
JSP
,
HTML
and
JavaScript
languages and
JQuery
library are used. The web server used is
Apache Tomcat
, since it can
interpret
JSP
pages. The cartographic server used by the system is
Geoserver
7
, since it is developed as a
J2EE
application and can be executed
on a
Tomcat
server. This way, the system requires only one server.
Postgres
with the
Postgis
extension is used as database management system. Two
geographic datasets were used, subsets of data from the
BDTOPO®
and
6
http://owlapi.sourceforge.net/
7
http://geoserver.org/display/GEOS/Welcome
