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We address the problem of data and information interoperability in the Earth System Science information domain. We believe that well-established architectures and standard technologies are now available to implement data interoperability. In particular, we elaborate on the mediated approach, and present several technological aspects of our implementation of a Mediator-based Information System for Earth System Science Data. We highlight some limitations of current standard-based solutions and introduce possible future improvements.

The First Periodic Technical Report explain the work carried out during the First reporting period (Month 1- Month 17) of ERA-PLANET project, in line with the Annex 1 to the Grant Agreement and include an overview of the project results towards the objective of the action in line with the structure of the Annex 1 to the Grant Agreement including summary of deliverables and milestones, and a summary of exploitable results and an explanation about how they can be exploited. ERA-PLANET "the European Network for Observing our Changing Planet" is an ERA-NET Co-fund action under the EU Horizon 2020 Framework Programme (Grant Agreement number 689443), which aims to strengthen the coordination of European research programmes in the field of Earth Observation (EO), within the Group on Earth Observations (GEO, https://www.earthobservations.org/index.php) and the European Earth observation Copernicus programme (www.copernicus.eu).

Once the most industrialized republic of the Soviet Union, Armenia inherited a dramatic ecological situation from the Soviet era. As the key national environmental academic entity, the Center for Ecological‐Noosphere Studies (CENS) of the National Academy of Sciences of the Republic of Armenia has a strong national role in delivering authoritative environmental information and data sets. To enhance data sharing towards its stakeholders, CENS engaged in recent years in several international capacity building projects directed to the setting up of an environmental Spatial Data Infrastructure (SDI). These activities were successful in showing the potential of data sharing in Armenia, to gain visibility in the country and the South Caucasus region, and to start engaging in international voluntary partnerships such as the Group on Earth Observations (GEO). CENS now envisions to scale up its SDI infrastructure to an environmental national SDI (nSDI) in order to support a wider range of geospatial services. This paper discusses several aspects and challenges of the envisioned strategy. First, we present how the current components of the implemented SDI benefit the scientific and environmental communities in Armenia. Second, we examine how the EGIDA methodology can be applied to support the process of scaling up the infrastructure to become a nSDI, one of the pilot studies in the EU/FP7 EOPOWER project. Finally, we discuss the potential of future full‐scale provision of geospatial services in Armenia and how these could benefit the various stakeholders involved in Armenia and in the South Caucasus region.

The OGC netCDF encoding supports electronic encoding of geospatial data, that is, digital geospatial information representing space and time-varying phenomena. This standard specifies the CF-netCDF data model extension. This standard specifies the CF-netCDF data model mapping onto the ISO 19123 coverage schema. This standard deals with multi-dimensional gridded data and multi-dimensional multi-point data. In particular, this extension standard encoding profile is limited to multi-point, and regular and warped grids; however, irregular grids are important in the CF-netCDF community and work is underway to expand the CF-netCDF to encompass other coverages types, including irregular gridded datasets.

This Discussion Paperproposes a set of conventions for managing uncertainty information within the netCDF3 data model and format: the NetCDF Uncertainty Conventions (NetCDF-U)

This document describes the activity which was done by the GEOSS Common Infrastructure (GCI) Research WG of the "GEOSS Architecture Implementation Pilot" (Phase 5).

In this second of a two-part article Massimo Craglia and Stefano Nativi explore the brokerig framework developed in EuroGEOSS and its demonstrable need for a radical rethink of the philosophy behind GEOSS and similar data infrastructures

GEOSS envisions a future wherein decisions and actions for the benefit of humankind are informed by coordinated, comprehensive and sustained Earth observations and information. Ultimately, this requires the ability to integrate information across scientific domains to address issues at regional and global levels. EuroGEOSS, an EC-sponsored FP7 project, has built an initial operating capability (IOC) in the three strategic areas of drought, forestry and biodiversity to facilitate and demonstrate multi-disciplinary applications. EuroGEOSS has implemented a brokering service that allows finding and accessing data from a wide range of standards and domainspecific practices including the use of a semantically rich querying capability. The paper presents the functionalities achieved by EuroGEOSS. The paper also presents the impact of advanced services through an assessment of societal benefits of the extended information availability.

In the framework of the FP7 ISTIMES project (Integrated System for Transport Infrastructures Surveillance and Monitoring by Electromagnetic Sensing), we have designed a distributed, real-time, Web-based information system for sensor-based transport infrastructures monitoring applications. The overall aim of the ISTIMES project is to make critical transport infrastructures more reliable and safe, providing real-time, detailed information and imagery of the infrastructure status, to improve decision support for security stakeholders, by means of non-destructive electromagnetic monitoring, exploiting heterogeneous state-of-the-art insitu sensors and specific satellite measurements. From an ICT point of view, ISTIMES aims at the design of an open networked architecture capable of integrating measurements from a wide range of remote and in-situ sensors. Our main contributions have regarded: the formalization of system users and use-cases; the design of the service infrastructure, including peculiar value-added mediation services; the identification of the system components and of possible technological implementations. The ISTIMES system is a middleware framework founded on a Spatial Data Infrastructure, hence enabling the implementation of individual test-bed applications, customized to the transport infrastructure of interest. ISTIMES is an ideal test case for the Event Architecture paradigm, which naturally accommodates asynchronous events from disparate sources, e.g. a constellation of autonomous sensors deployed onto an infrastructure. Besides, ISTIMES constitutes a valuable real-world application for the current best practices and standards in multi-sensors, real-time monitoring systems, and its feedback may contribute to their future evolution.

Interoperability has become a key concept amongst scientific communities, in particular with the focus of heterogeneous data discovery and access as well as services discovery. Our work is developed in the context of the Global Earth Observing System of Systems (GEOSS) Interoperability Process Pilot Project and it demonstrates the feasibility of interoperability between different communities. The Global Biodiversity Information Facility (GBIF) provides through its web portal and services a huge amount of primary species occurrence data, acquired and uni- fied from different data providers. GBIF uses standards relevant to the biodiversity community (e.g. Darwin Core, Taxon Concept Schema), as well as newly introduced concepts and interfaces. The Open Geospatial Consortium (OGC) Catalogue Service for the Web (CSW) is a service that can perform discovery of geospatial data and services, returning results in the form of profiled metadata. In particular the ISO Application Profile (AP) defines a particular set of metadata well known in the geospatial community (ISO 19115/ISO 19119). We make GBIF biodiversity data and services available through a CSW ISO AP catalog; this is done by means of a mapping of the GBIF data model and GBIF services to their CSW ISO AP equivalents. Regarding the data model mapping, the main work was to design the mapping be

In this paper the concept of the Siberian Earth System Science Cluster (SIB-ESS-C) being established at the University of Jena (Germany) is presented. SIB-ESS-C is a spatial data infrastructure for remote sensing product generation, data dissemination and scientific data analysis. The prime objective is to enable researchers to extract information on the state of the Siberian environment and the changes that are occurring using Web-based tools. The region under study covers the entire Asian part of the Russian Federation from the Ural to the Pacific Ocean including the Ob-, Lenaand Yenissey river catchments. Taking into account the large extent of this region the focus is on remote sensing data as the primary data source. A key aspect is to create and analyze long-term time series of various environmental parameters derived from Earth Observation data. The SIB-ESS-C infrastructure is to provide the technical means by which remote sensing time series can be created, distributed and analyzed through Web-based tools. The development of the SIB-ESS-C system follows a service oriented architecture (SOA) approach. Interoperable Web services are being implemented based on standards published by the Open Geospatial Consortium (OGC) and the International Organization for Standardization (ISO). The main components of the system comprise a Catalogue Service (CSW) publishing metadata on available data products and services, Feature and Coverage Services (WFS, WCS) providing direct access to existing datasets and Web Processing Services (WPS) for spatio-temporal analysis and visualization.

In the last years REST (Representational State Transfer) has emerged as an alternative to existing approaches for Web applications development. Indeed, its characteristics of scalability and simplicity make it appealing for building complex Web services systems. Anyway an investigation is required to verify if and how it can be applied to specific domains. We analyzed the case of Geospatial services also building a prototype of a RESTful OGC WCS implementation. The WCSplus community discussions were considered as a starting point for our work. REST is an architectural style for distributed systems defined to describe the Web architecture and to guide its future evolution. It allows to describe a set of ResourceOriented architectures which share six constraints: client-server and stateless interaction, uniform interface, caching and code-on-demand (optional) support, multi-layer distribution. The fundamental characteristics of REST is the uniform interface which is defined by four interface constraints: identification of resources; manipulation of resources through representations; self-descriptive messages; and, hypermedia as the engine of application state. It is a generic (not resource-specific) interface, in the sense that it allows to perform the same set of actions on all the resources. Thus it exposes very basic operations for retrieving and sending representations of resources. Different application-level protocols can be used, but the most common implementation makes use of HTTP with GET/POST/PUT/DELETE verbs detailing the four basic operations mapping the CRUD (Create, Retrieve, Update, Delete) pattern. Since representations are generally encoded in XML, REST applications looks much like the traditional Web applications, usually referred to as POX-HTTP (Plain-Old-XML over HTTP), which implements Web Services using HTTP-GET and HTTP-POST operations. The uni

The CYCLOPS project is an FP6 Specific Support Action which aims to bring together two important Communities: GMES and Grid, focusing on the operative sector of European Civil Protection (CP). Recently RISICO, an operative Italian Civil Protection application for wild fires risk assessment, has been ported to gLite by the CYCLOPS working group. RISICO presently runs in Grid accessing data stored using various proprietary formats in a gLite Storage Element. GLite is the Grid middleware developed by the EGEE European project (Enabling Grids for E-sciencE). As a further step we discuss which benefits could be granted to RISICO, realising an intermediate layer of geospatial web-services between the CP application and gLite. All the web-services implement standard interfaces specified by the Open Geospatial Consortium (OGC). In this case the georeferenced data will be stored in standard formats (GRIB/NetCDF) and will be accessed through standard interfaces. The workflow will be as follows: o The CP user selects an area in which the model should be run, selects the input data URIs and indicates an appropriate priority for the action. o Our application, exposing the Web Processing Server (WPS) interface, receives the request, evaluates the input size and the priority, and then activates various independent data access services. These, implementing the Web Coverage

This presentation will introduce the CYber-Infrastructure for CiviL protection Operative ProcedureS (CYCLOPS) project, funded in the priority: research Infrastructure - communication network development of the European FP6. CYCLOPS is a Specific Support Action of EGEE. CYCLOPS main objective is to bridge the gap between Grid and GMES communities making Civil Protection people be aware of the services provided by Grid infrastructures, and, at the same time, letting Grid researcher to be aware of Civil Protection specific requirements and service enhancement needs. The Global Monitoring for Environment and Security (GMES) concept was endorsed by the EU Commission to gather and use all available data and information in support of sustainable development policies. GMES has the potential to stimulate economic growth by creating innovative value-added services. The challenge for GMES is to use these services to enable decision makers to better anticipate or mitigate crisis situations and management issues related to the environment and security. The Final Report for the GMES Initial Period recognized the European Civil Protection (CP) as one of the GMES service categories. This report outlines the importance to develop enabling einfrastructures and virtual organization services to serve specific GMES applications. Indeed, the EU EGEE (Enabling Grids for E-Science in Europe) project provides a powerful GRID platform to implement services for specific application Communities. However, GRID evolution has mainly focused on technology, while, GMES services have mostly been user-oriented. Thus, there is a need to cross-disseminating the approaches, requirements and visions of the diverse Communities, in order to fully exploit the GRID capabilities for GMES applications. CYCLOPS brings together these two important Communities: GMES and GRID, focusing on the operative sector and needs of European CP. CYCLOPS main actions include: 1) To disseminate EGEE results to the CP Community, assessing EGEE infrastructure for CP applications. 2) To provide the EGEE Community with knowledge and requirements that characterize the CP services. 3) To evaluate the possibility to utilize the present EGEE services for CP applications, developing the research strategies to enhance EGEE platform. A valuable case in point is the Forest Fires use scenarios. 4) To develop the research strategies to enhance Grid platform, especially for Earth sciences resources, providing a sort of roadmap for the future European research activities.

Over the past decade visualization and analysis of geospatial data followed the general trend in information technology from monolithic desktop applications towards loosely coupled Web Services. In order to achieve interoperability among these services standard interfaces are required. The standards and specifications published by the Open Geospatial Consortium (OGC) and the International Organization for Standardization (ISO) form the basic set on which such service-oriented architectures (SOA) can be build. With respect to online data visualization a map like representation of spatial content has found widespread use, especially as part of Spatial Data Infrastructures (SDI). In combination with metadata catalogues the primary aim of these map services is data publication and distribution, hence the capabilities are limited to viewing or browsing (e.g. zoom, pan, identify). Only a few examples exist enabling users to analyse data (e.g. calculating statistics or merging different data layers) through a web interface or Web Service. In this paper first results are presented from research conducted on the implementation of a OGC Web Processing Service (WPS) for online analysis of Earth observation time series data. Earth observation data at regional to global scale has been collected with various sensors and satellite systems for more than three decades. The amounts of data acquired seem to have outpaced our ability to exploit and analysis it. With aid of consistent data products (e.g. MODIS suite of land surface products) and the advancements in information technology and in particular the OGC/ISO standards for Web services the basis to overcome this shortfall is avail

At the Boulder OGC (Open Geospatial Consortium) Technical Committee meetings, Unidata hosted a special Interoperability Day to address the use of standard interfaces (CS-W/ebRIM, WFS, WCS, SOS, GML) for providing access to data currently served via THREDDS, OPeNDAP, netCDF-CF and IDD/LDM technologies. The primary data served is Weather, Climate and Ocean data from the community, sometimes referred to as Fluid Earth Sciences (FES). Subsequent discussions have led to a subset of participants in the OGC GALEON (Geo-interface for Air Land, Envrirohment, Ocean NetCDF) Interface Experiment to embark on a revised approach to contributing to the evolution of coverage-related standards. The overall objective remains the development of practical and concrete ideas for

Ecological forecasting-making predictions about the ecological consequences of various types of change-is constrained by a variety of factors, including computer model interoperability. This, in turn, is limited by technical barriers, such as semantic and format consistency, and non-technical ones, such as model isolation that results when sponsors use a "stovepiped" funding approach rather than an integrated one. Because these constraints limit the types of ecological questions that can be addressed, they need to be overcome if decision makers are to obtain the information they require to make informed decisions. The problem of limited model interoperability exists, to varying degrees, in all disciplines that rely on computer models, including hydrology, air quality, and the ocean sciences, among others. One solution is being called the Model Web, a concept for an open-ended system of interoperable computer models and databases communicating via Service Oriented Architectures. The Model Web would consist of a distributed, multidisciplinary network of independent, interoperating models (plus related datasets and sensors). Like the World Wide Web it would grow organically, without central control, within a framework of broad goals and data exchange standards or guidelines. These are under discussion but they should emerge naturally from the modeling community; no single

Coverage concept represents the mapping from a domain (e.g. spatio-temporal domain) to parameter values where parameters value types are common to all the locations within the domain. For example, a spatio-temporal domain consists of a collection of direct positions in a coordinate space that may be defined in terms of up to three spatial dimensions as well as a temporal dimension. Coverages are the prevailing data structures in a number of application areas, such as remote sensing, meteorology, and mapping of bathymetry, elevation, soil, and vegetation. Examples of coverages include rasters, profiles, trajectories, triangulated irregular networks, gridded data, and polygon coverages. Hence, coverage is a general geospatial information concept representing space and time-varying phenomena; virtually, any geospatial data may be viewed as an instance of a coverage type. Most of the different Geospatial Information Communities (GICs) are characterized by acquiring, managing, processing and serving diverse coverage types which are described using specific metadata. In order to support interoperability, the implementation of standard services to access the different coverage types is becoming more and more important. The presentation will discuss the coverage access services as far as simplicity, effectiveness and interoperability are concerned. The Earth and Space Sciences, GIS, and Society perspectives will be introduced. The need for a robust abstract model underpinning different implementation models is addressed. These specific implementation models are important to accommodate heterogeneous GIC needs and use scenarios. In fact, access services may play an important role in order to map complex datasets to simpler coverage types, introducing explicit semantics.

Earth scientists are engaged in integrating knowledge stemming from different disciplines concerned with the constituent parts of the complex Earth system. The goal is to understand Earth's properties as a whole and thereby deliver benefits to society. The scope and complexity of Earth system investigations demand the formation of distributed, multidisciplinary collaborative teams, which presents both scientific and technological challenges. The information systems used by the different disciplines are characterized by heterogeneous and distributed data and metadata models, different semantics and expertise, diverse protocols and interfaces, and different data policies and security levels. We describe how the Global Earth Observation System of Systems (GEOSS) infrastructure facilitates the formation of these distributed, multidisciplinary and collaborative teams. Initiated in 2005 by the GEO Architecture and Data Committee, the GEOSS Interoperability Process Pilot Project (IP3) is a medium for reaching interoperability between disparate components contributed to GEOSS from multi-disciplinary Earth and Space Science communities. In 2007 one of IP3's key successes was an end-to-end demonstration that combined biological species data, accessed through the GBIF (Global Biodiversity Information Facility) contribution to GEOSS, and climate model output data, part of the WMO's Information System's contribution to GEOSS, accessed through NCAR, and seamlessly fed the data stream into an ecological niche model (ENM). The ENM runs in an open modeling framework to produce a new product displaying the impacts of climate change on the geographic distribution of selected

The atmospheric and geospatial communities are still separate worlds with their own tools and data formats. It is extremely difficult to easily share data among scientists representing these communities without performing some cumbersome conversions. ADAGUC aims to reduce the need for scientists to invent their own converter tools. Selected space borne atmospheric datasets will be made accessible to a GIS system in order to be submitted to data comparison, resampling, selection, manipulation and visualization. The user community will be intensively involved in the project to obtain a high fitness for use. The first ADAGUC workshop (Oct 2006) was attended by a large group of users from both the atmospheric and GIS community and resulted in a better understanding of user needs that are currently translated into specifications for the user requirements document of ADAGUC. The deliverables of this project are: Open Source conversion tools, selected atmospheric datasets in a GIS-friendly format and a web service to demonstrate the usability of the above to the geospatial and atmospheric community.

While some two million plus species have been described, and many millions more remain to be discovered, climate change threatens to commit 15 to 37 per cent of these to extinction by 2050, accelerating a dangerous trend that land use change has already set in motion. An extinction episode of this magnitude would likely severely degrade the quality of vital ecosystem services, such as nutrient cycling, atmospheric regulation, soil formation, water purification, and pollination, upon which the human enterprise relies. Scientists are presented with the formidable challenge of assessing likely impacts of unprecedented interactions between rapid climate and land use changes, predicting how those impacts will unfold into the future, and providing policy options to decision-makers. These issues have been highlighted in stark terms in the newly released Fourth Assessment Report of the Intergovernmental Panel on Climate Change.1

Spatial Data Infrastructure:SDI (also known as Geospatial Data Infrastructure) is fundamentally a mechanism to facilitate the sharing and exchange of geospatial data. SDI is a scheme necessary for the effective collection, management, access, delivery and utilization of geospatial data; it is important for: objective decision making and sound land based policy, support economic development and encourage socially and environmentally sustainable development. As far as data model and semantics are concerned, a valuable and effective SDI should be able to cross the boundaries between the Geographic Information System/Science (GIS) and Earth and Space Science (ESS) communities. Hence, SDI should be able to discover, access and share information and data produced and managed by both GIS and ESS communities, in an integrated way. In other terms, SDI must be built on a conceptual and technological framework which abstracts the nature and structure of shared dataset: feature-based data or Imagery, Gridded and Coverage Data (IGCD). ISO TC211 and the Open Geospatial Consortium provided important artifacts to build up this framework. In particular, the OGC Web Services (OWS) initiatives and several Interoperability Experiment (e.g. the GALEON IE) are extremely useful for this purpose. We present a SDI solution which is able to manage both GIS and ESS datasets. It is based on OWS and other well-accepted or promising technologies, such as: UNIDATA netCDF and CDM, ncML and ncML-GML. Moreover, it uses a specific technology to implement a distributed and federated system of catalogues: the GI-Cat. This technology performs data model mediation and protocol adaptation tasks. It is used to work out a metadata clearinghouse service, implementing a common (federal) catalogue model which is based on the ISO 19115 core metadata for geo-dataset. Nevertheless, other well- accepted or standard catalogue data models can be easily implemented as common view (e.g. OGC CS-W, the next coming INSPIRE discovery metadata model, etc.). The proposed solution has been conceived and developed for building up the "Lucan SDI". This is the SDI of the Italian Basilicata Region. It aims to connect the following data providers and users: the National River Basin Authority of Basilicata, the Regional Environmental Agency, the Land Management & Cadastre Regional Authorities, the Prefecture, the Regional Civil Protection Centers, the National Research Council Institutes in Basilicata, the Academia, several SMEs.

As observational and model output datasets in the FES (Fluid Earth Sciences, mainly oceanography and atmospheric science) increase in resolution, there is an increasing demand for information systems that interoperate between the GIS and FES realms However, differences in the way the two communities think about their data can give rise to difficulties in integrated analysis and display of datasets from the two disciplines. Moreover, new kind of services (functionalities) are getting more and more important: interoperability services. They require data models suited for enabling web service to "understand" and easily exchange FES datasets. These data models must be particularly accurate on metadata and encoding model, which enable the effective sharing of data content and meaning, and hence the real system interoperability. XML encoding dialects, based on semistructured data models, seems to be an effective technology to facilitate FES and GIS interoperability. In our vision, these data models are extremely useful to achieve applications interoperability. They are useful to interconnect sibling services implemented on heterogeneous applications. A conceptual, abstract view of differences between the data models of the FES and GIS communities is presented, as well as a schematic description of where the data systems overlap and where they are distinct from each other. Well accepted data models (i.e. netCDF and OpenGIS/ISO coverage) are considered and presented. Examples of significant XML dialects (i.e. Markup Languages) for both communities are presented (i.e. GML and ncML), discussing an innovative mediation solution approach: the ncML-GML. This XML dialect is an extension of the netCDF Markup Language (ncML); it enables encoding of netCDF datasets in terms of the Geography Markup Language (GML) elements. It was conceived to facilitate interoperability between the FES and the GIS communities. NcML-GML leverages the ncML ability to encode multi-dimensional arrays, and the wide acceptance of GML for encoding geo-spatial metadata. NcML-GML is also particularly useful where both FES and GIS semantics and metadata content are required. For interoperability purpose, according to the Service Oriented Approach, it is possible to distinguish different service tiers; each tier contains systems and tools which implement its specific task. Such a framework for the FES and the GIS information communities is analyzed and discussed. The heterogeneity of existing FES protocols and data models is outlined. The interoperability opportunities laid by the OGC's specifications are briefly introduced. The need of achieving the two communities' frameworks interoperability, and its importance for enabling effective Spatial Data Infrastructures (SDIs) are introduced and discussed. The need for data model crosswalks as well as access and discovery protocol adapters is outlined. The mediation approach is a valuable technique to address this issue. A valuable framework, based on well-accepted protocol and data model interoperability standards is briefly presented and a main experimentation of its adopted mediation solution is reported..

Several geo-information communities (e.g. oceanography, atmospheric science, earth observation, etc.) have developed tailored metadata specifications for data discovery, evaluation and use. They conceived these models either profiling standard models (e.g. ISO 19115 metadata specification) or enriching existing and well- accepted data models (e.g. THREDDS/OPeNDAP/netCDF data model) in order to capture and describe more semantics. These metadata profiles have generated a set of related catalog services that characterize the different Communities, initiatives and projects (e.g. INSPIRE, MERSEA, LEAD, etc.). In addition, specific catalog services have been generated by profiling standard catalog services which were designed to accomplish the general requirements coming from the geo-information community (e.g. OGC CS-W). Indeed, to implement catalog services interoperability is a near-term challenge in support of fully functional and useful discovery and sharing infrastructures for spatial data. To implement catalog services interoperability requires metadata profiles harmonization and discovery protocols adaptation and mediation. In an over- simplified way, these solutions may be considered catalogue of catalogues or catalogue broker components. We conceived a solution for making several well-accepted catalogue services interoperable (e.g. OGC services, THREDDS, ESA EOLI, MERSEA CDI, etc.). This solution has been experimented as a stand-alone application tool, called GI-go. More recently, we re-engineered this approach as a service-oriented framework of modular components. We implemented a caching brokering catalog service which acts as a broker towards heterogeneous catalogues services dealing with IGCD (Imagery Gridded and Coverage Data). This service is called GI-cat; it implements metadata harmonization and discovery protocols adaptation. GI-cat supports query distribution allowing its clients to discover and evaluate the datasets, managed by the federated heterogeneous catalogs, via a unique interface. Presently, it is possible to finalize selections by any combination of the following criteria: spatial extent, temporal extent, keywords (free text) and data source (i.e. Where, When, What, Who). We are experimenting another component, called GI-profile, which implements mediation services to profile the generated unified output according to a well-known metadata models (e.g. OGC CS-W). Connecting these two components and a specific GUI it is possible to work out catalog tools, tailored for different Communities, which work as real brokers.