Global Drought Monitoring Service through the GEOSS Architecture ...

Architectural Implementation Pilot, Phase 3 Version: 2.0
Global Drought Monitoring and European Drought
Observatory-Water SBA Engineering Report
Date: 11/Feb/2011
submits the queries to the EuroGEOSS Broker
Use Case: Discovery: Client Search of Metadata
Step 03.2: The EuroGEOSS Broker mediates the query request, distributing it to its federated
services
Step 03.3: The Decision maker uses the Decision Support System to select one or more drought
hazard related information datasets, among the ones returned by the query
Presentation of Reachable Services and Alerts
Step 03.4: The Decision Support Tool submits an access request to the EuroGEOSS Broker in
order to retrieve the user-selected drought hazard information datasets
Interact with Services
Step 04: Visualization and Assessment of Information
Step 04.1: The Decision Support Tool displays the accessed drought hazard information datasets,
combining them with the potential hazard layer
Step 04.2: The decision maker assesses the drought hazard impact
5.2.1 Advanced Semantic Search
Scenario Step 03 embodies the advanced semantics incorporated into the European
Drought Implementation.
Upon being notified of a drought alert in an area of interest, the decision maker (drought
expert) can go online to consult the common EuroGEOSS broker-EDO interface. For example,
the EuroGEOSS broker incorporates both: 1) Discovery Augmentation Component (DAC) and
2) the workflow engine, which increases the power of search by integrating together catalogue
and semantic components. In other words, the workflow engine browses the semantic
repositories to retrieve concepts. Once the expert drought user has identified a concept of
interest, the resources (datasets and services) linked to each of these concepts can be retrieved.
5.2.1.1 Ontology Registration
An ontology is a technology for organizing information which includes the organization
of the information together into relationships that are reminiscent of the class structure found in
programming languages. The ontologies are stored within the Semantic Network within DIAS,
which preserves this class structure.
5.2.1.2 Geographic Registration
As can be seen in Figure 11, two types of ontological information are developed and
expanded: 1) lexicographic ontologies, i.e., ontologies of scientific disciplines and remote
sensing; and 2) geographic ontologies, as represented by gazetteers. A gazetteer is defined as a
reference for information about places and place names used in conjunction with an atlas (hill et
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