DISPRO: A Web-Based Distributed Architecture for Coastal Zone Management

by Éamonn Ó Tuama (1), Clive Best(2), Torill Hamre(3) (1) Coastal & Marine Resources Centre (Ionad Acmhainní Cósta is Mara) - ERI, University College Cork (IE)
(2) Joint Research Centre (JRC) - Institute for the Protection and Security of the Citizen (IPSC), Ispra (IT)
(3) Nansen Environmental and Remote Sensing Center (NERSC), Bergen (NO)

Editor's Note: This is an excerpt of a paper presented at CoastGIS 2003 in Genoa, Italy in October 2003. Used by permission of the authors. The complete paper is online.

Introduction

DISPRO is a work-in-progress prototype for an advanced Web-based information system to improve management of pollution crises in coastal and ocean regions of Europe. DISPRO, a pan-European, multi-institutional project, uses a Web-based distributed architecture, incorporating OGC Web Services and other complementary Web services. This architecture, consistent with the INSPIRE general model for an SDI (Spatial Data Infrastructure), is multi-tier (client, middleware, data layers) and includes four main groups of components: user applications, geo-processing and catalogue services, catalogues and content repositories. The principles guiding the design are to follow closely the INSPIRE, OpenGIS and W3C standards, and to use open source software where available. Following open standards and protocols provides a high degree of flexibility while the distributed nature of the system allows each institution to retain control of its own data. DISPRO is being developed as part of the EU (Information Society Technologies) IST funded project DISMAR.

DISMAR (Data Integration System for Marine Pollution and Water Quality), a project funded under the EU IST Programme, brings together 17 organizations from six countries: Norway, Germany, Italy, France, United Kingdom, and Ireland. The objective of the DISMAR consortium is to produce a state-of-the-art, Web-enabled, marine management system. The project started in August 2002 and runs for three years.

The prototype of the system, known as DISPRO, will focus on providing decision support for the management of oil spill and algal bloom incidents. It is being developed in two phases. DISPRO-1 will be available in mid 2004, and will undergo extensive user trials to assess the quality of delivered products and the user friendliness of the prototype. The experiences and feedback gained will aid in the development of the final system (DISPRO-2) to be completed by early 2005. While the aim is to provide a scalable, pan-European system, the prototype will confine itself to six demonstration regions (North Sea/Skagerrak, German Bight/North Sea, Coast of France, Coast of Italy, Coast of U.K., South-West Ireland).

Implementing DISPRO

DISPRO will use an architecture consistent with the INSPIRE general model of an SDI. It will constitute a multi-tier system (Fig.2) featuring diverse end user applications communicating with various application servers which are in turn linked to the data repositories. There are several components in each tier of the system.

Potential enabling technologies for implementing DISPRO include:

• Web Server (HTTP server): Apache HTTP Server
• Web Map Server: The WMS can be implemented using a simple script (e.g. in Python or Perl) or a more sophisticated application such as University of Minnesota MapServer, or any other OpenGIS WMS supporting software.
• Web Feature Server: University of Minnesota MapServer, GeoServer, or any other OpenGIS WFS supporting software.
• Database - Relational: PostgreSQL; MySQL
• Database - Native XML: Exist; Xindice
• Spatially enabled database: PostgreSQL-PostGIS
• News Feed: RSS
• XML publishing/processing framework: Apache Cocoon

DISPRO Portal

The portal is the front-end to the prototype providing access to all features of the system through a web browser. The server hosting the portal will be based at CMRC in Cork (CMRC DISPRO). Several types of client applications are available within the portal.

• The catalogue browser provides an interface to the catalogue, the core of the system. It allows the user to browse and search the catalogue for geodata, services and other resources. Depending on the type of request, an appropriate client is displayed. For example, if the user requests a particular geo-processing service, the input form for that service will be generated dynamically for presentation in a geo-processing client and communicate directly with the application server for submission.
• The map viewer client provides the interface for interacting with the GIS. It may rely on the basic functionality of the browser (HTML, CSS, JavaScript), or alternatively, be enhanced with plug-in applications such as Java applets and SVG viewers.
• The news client displays the RSS news feed which provides news alerts on new and updated data, pollution events and service notices (e.g. an alert on completion of an oil drift model run). Live News will also be syndicated from a third party source, probably the Europe Media Monitor.
• The file upload client allows a user to upload files to particular directories.

DISPRO Demonstrator

The DISPRO portal provides the entry point to the system. The first essential feature required here is a facility for selecting a region. This will be implemented as a static image map: the user simply clicks on one of the six outlined demonstration areas to select it. In a fully functional, European-wide system, the map would be presented by a GIS client where the user can drag-select the mouse over the map to define a bounding-box of the region of interest. Once the user selects a demonstration region, the web page for that region is loaded. The essential features displayed here are:

- an OpenGIS WMS/WFS client, initially set to display a base map of the region (1) with dynamically generated legend (3) and reference map (5); the client will provide basic GIS functions (4) such as selecting and overlaying layers (vector and raster) of interest, panning and zooming, and simple querying; raw feature data (in GML) will also be available.

- a dynamically generated list of layers available in the GIS (2); this will be continuously updated as new geodata is submitted by data providers; these will include observations (in situ, aircraft, satellite), derived parameters (e.g., potential oil spill location and probability), or forecasted parameters (e.g., oil drift model predictions); the full metadata information for a layer is most conveniently made available as a hyperlink from the layer title.

- the catalogues list (6); each title in the catalogue list will link to a separate catalogue interface, e.g., "geo-processing services".

- the news feeder (7); this will display news items; an SMS and e-mail alerting system can also be implemented for time-critical operations.

The Catalogues

The catalogues provide access to all resources in the system (geodata, geo-processing services, documents, etc.). The geodata is presented through the GIS client (2) while the services and documents are presented through separate catalogue interfaces. The prototype of the geo-processing services catalogue initially displays a list of the geo-processing services available for the region. Each geo-processing service will describe its required input parameters in a schema defined in XML. When the user selects a service, a form is automatically generated from the schema and displayed. For instance, the Met.no Oil Spill Model, OD3D, calculates the drift and evolution of oil "superparticles" at both surface and sub-surface. It accepts a request in the form of an XML file and returns a forecast (a time series of the characteristics of each superparticle) in the form of two products, i) an XML file describing the characteristics (position, depth, mass, chemical properties, etc.) of each superparticle as an hourly time series, and ii) a GRIB-in-XML file providing currents, water temperature, salinity, water level, winds, atmospheric pressure as 2D fields (hourly) at standard depths.

Once the model run is completed (it takes about 30 minutes), the products (files) are delivered to the DISPRO server and the user is alerted (via their pre-selected choice - RSS, E-mail, SMS) as to their availability. The products are accessible via a hierarchical menu system.

Each product will have a unique URL (following the REST guidelines), e.g., http://dispro.ucc.ie/OD3D/output_2003_07_22_11_22.xml, and is thus bookmarkable for future access. When a product is selected (by clicking on its title in the hierarchical menu), an appropriate viewer will be launched, e.g., OD3D XML output could be presented as an SVG animation, whereas, the GRIB product would require a Java plugin for visualization.

The documents catalogue interface is similar to that for the geo-processing services. It displays a hierarchical list of all documents available for the region. These can be arranged logically into appropriate categories, e.g., 'Fire Fighting', 'Oil Spills', 'Nature Reserves'. Clicking on a document title, e.g., 'Bantry Bay Contingency Plan', launches the PDF viewer in the right hand part of the window.

Conclusion

Implementation of the prototype is now underway, the Skagerrak/North Sea providing the first test case, with other cases following in an iterative cycle of development. By contributing to the harmonization and standardization of observing systems, data, models and management systems, DISPRO will demonstrate the benefits of an SDI for Europe as envisaged by INSPIRE.