Today, Spatial Data Infrastructures (SDIs)
are primarily used to share and access distributed spatial data. However,
the usefulness of SDIs can be improved by developing web services that
are also capable of processing the shared data in order to tailor the
results to the needs of the user. In this context, the Open Geospatial
Consortium (OGC) has established standards for processing spatial
data by introducing a discussion paper on the topic of a Web Processing
The goal of this thesis was the design and implementation
of an interoperable Web Processing Service for Aggregating Spatial Data.
The basis was a concrete use case concerning the combination of forest
fire records with administrative boundaries within the EU funded project
“Open Architecture and Spatial Data Infrastructures for Risk Management”
The developed Aggregation Service combines fire ignition
locations which are made available as point data and administrative units
which are made available as polygon data. It calculates the number of
fires in the administrative units and aggregates the related attribute
values of the fire data. Two steps are necessary: Spatial Join (based
on the relational algebra operation join and topological relationships)
and Aggregation (based on relational algebra aggregate functions). These
are provided by the two service processes “Join” and “Aggregate”.
The conceptual design was mapped to the OGC WPS specification
(see figure below for the mapping of the Join Process) and for the prototypical
implementation the open source 52°N WPS framework, the JAVA programming
language and JUMP libraries were used.
The service provides three processes, is extensible, and
can be connected with other services in a service chain.