The TIGER-NET Water Observation and Information System (WOIS) can be seen as a multipurpose system consisting of a storage container for the geodata (Database Module), extraction and processing of the EO data through customized processing facilities (EO data processing module), modelling tools (Hydrological modules)as well as visualisation and analysis tools (GIS decision support module).
This multipurpose system is built from different open source software packages all supported by Microsoft operating systems and with full internal as well as external interoperability.
Database module
The database module acts as the main building stone, where all pre-processed and user derived geodata is being stored in a spatial database architecture and associated file repository. Moreover, the WOIS database allows automatic retrieval of EO data as well as data exchange with operational systems of the users.
EO processing module
The EO data processing module enables functions and methodologies for image processing and analysis of the user required EO data stored in the user database.
Hydrological module
Dedicated tools for a satellite earth observation based hydrological modelling, simulating the land phase of the hydrological cycle, providing discharge forecasts into user-defined sub-catchments as well as water demand on land cover basis.
Decision Support module
The GIS module empowers the users to retrieve, visualize and analyse spatial data and information into knowledge and provide the basis for decision support.
The WOIS has been designed around Quantum GIS (QGIS), which acts as the front-end Graphical-User-Interface (GUI).
The other components of WOIS are:
- GRASS GIS (large toolbox of raster and vector analysis algorithms),
- BEAM and NEST (processing of optical, thermal and radar ESA data products),
- Orfeo Toolbox (high resolution image processing),
- Soil Water Assessment Tool – SWAT (hydrological modeling),
- R scripts (statistical and graphical tools),
- PostGIS (spatial database) and
- Sentinel-1 Toolbox.
The functionality from the different software components are integrated using the SEXTANTE spatial data analysis library which provides a framework for incorporating algorithms from the various providers (such as GRASS GIS, BEAM, etc.) into QGIS. A key advantage of SEXTANTE is the ability to seamlessly use functionality from different providers for data processing and analysis, and via a unique QGIS plugin it is possible to sequentially combine algorithms from the different providers into wizard-based processing i.e. standardised workflows of complex tasks with instructions
The plugin has been used to generate a workflow library with step-by-step guidance for the users to extract specific water information products. The workflows are first and foremost a help for the novice and intermediate users, while the more advanced users may choose to explore the full suite of algorithms and tools available from SEXTANTE in order to creating his/her own workflows. Moreover, pre-parameterized SEXTANTE models for certain products are provided to enable an automatized production for operational usage.
As part of the WOIS framework a PostGIS database is provided, enabling de-centralized operation of multiple user identities. A library of import/export function further ensures the integrate ability and/or connection to existing IT infrastructures and databases.
The WOIS enables the user to perform the required processing steps from the satellite EO data to the spatial hydrologic information solutions needed to support operational integrated water resource management.
