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
translations for each of the selected concepts/terms.
5.6.3 European Drought Observatory (Client) Query
EuroGEOSS DAC communicates with the EuroGEOSS Discovery Broker through the
OGC CSW ISO AP 2.0.2 interface. For each of the selected concepts/terms, EuroGEOSS
DAC creates a query that contains geographic (i.e. the envelope characterizing the specific
AOI), and multilingual Keywords constraints (i.e. the concepts/terms selected through the
EuroGEOSS/GENESIS Client Application). This set of queries is submitted to the
EuroGEOSS Discovery Broker. As shown in the “Drought—Europe” video, the user has
identified a geographic area on the map interface, while at the same time, highlighted and
clicked on a concept. Before sending back the results to the client, the EuroGEOSS DAC
groups them according to the matched concept/term.
5.6.4 WPS Request
The European Drought Observatory (EDO) WPS Client sends an Execute request to the
WPS Server, including references to the input thematic layers selected by the user (WCS
endpoint and coverage name).
5.7 Use of EuroGEOSS Semantic Discovery within the European Drought
Observatory (Returning back to the Scenario)
The User Interface to DAC includes two tabs: 1) “Search” and 2) “configuration.” The
process begins with a “Simple Search” text box, in which a user types in the overall query item
of interest “drought.” The “Advanced Search” panel becomes active, containing a text string box
in which the user types the keyword, underneath of which are buttons “Get concepts,” “relation,”
“extend node,” “clean selection,” and “search.” The “Get concepts” button obviously retrieves
the concepts, which are then displayed in graph form as nodes on a tree or graph.
The “relation” button, when pressed, offers the selection of “more general terms,” “more
specific terms,” “corresponding terms,” and “related terms.” The color coding used in the graphs
are: 1) “orange” for more specific, 2) “yellow” for more general, and 3) “green” for
corresponding. For example, “drought indicator” is a “more specific” example of “drought.”
As shown in the demonstration video, a user can draw a box around an area of interest on
a map, while simultaneously having entered the concept of interest to the user. Then the search
results will be retrieved. The returning data matches the requested concepts. Then the selected
datasets can be displayed upon a map server (Scenario Step 04) (see section 6.4)
5.8 Interoperability Arrangements with GEOSS
We use the following service interface:
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