AN INTEROPERABLE PORTAL SUPPORTING PROTOTYPING GEOSPATIAL APPLICATIONS

INTRODUCTION NASA's Earth Observing System (EOS, including satellite sensors and satellite data-receiving systems) is generating more than two terabytes of geoscience data daily, and has archived more than four petabytes of data in its Distributed Active Archive Centers (DAACs). Among these datasets, about 34 million data products and 640 TB data were disseminated to more than 2 million distinct users in 2004 (NASA 2005). To further improve the usage of the data, NASA and its partner agencies identified 12 national applications (Birk et al 2006). These application areas integrate the earth observations, earth system modeling, and decision support tools to support national and societal needs, such as public health and coastal management. Integration of global earth observation data and earth system models in applications from regional to global benefit also helps to build the Global Earth Observation System of Systems (GEOSS, GEO 2005). The integration processes, for national applications and GEOSS applications, are illustrated in Figure 1: 1) Earth observation systems acquire data through remote sensors and in situ sensors. 2) The earth observation data are fed into earth system models or the decision-support tools. 3) The earth system modeling results are fed into decision-support tools. 4) The decision-support tools outputs are used for policy and management decisions. 5) The feedback from the policy and management decisions are used to improve earth observation systems and earth system models. Within the last few decades, geospatial information (such as observation data and simulation outputs) has been used widely for decision-supporting applications from a global level, such as the crop yield predictions for diplomatic use (Doraiswamy 2004), to a local level, such as the West Nile Virus surveillance (Gutro 2002). Each of the components involved in the applications is a valuable asset. With the objective to develop national applications and GEOSS applications by integrating these assets, it becomes important to share these assets in an interoperable and fast manner. Services provide an opportunity to achieve this requirement. For example, the geospatial components (see Figure 1) can be extracted and developed as different services: 1) The earth observation systems can be enhanced to provide interoperable data services. 2) The earth system models can provide simulation output as interoperable data or information services. 3) The decision-support tools can provide geospatial decision-support processing services. 4) The decision makers and practitioners can observe the impacts of decisions made and provide the impacts as a quality of service (QoS) feedback to optimize or improve the services involved in the process. [FIGURE 1 OMITTED] Many data and information services have been developed to share earth observations (such as the EOS Data Gateway where users can search and download or order data, EDG, 2006) and model simulations (such as the Global Modeling and Assimilation Office, which is responsible for global atmospheric phenomena simulations within NASA, GMAO, 2003). Online catalogs, such as the Federal Geographic Data Committee (FGDC) Clearinghouse (FGDC 1996), NASA's Global Climate Master Directory (GCMD, http://gcmd.gsfc.nasa.gov/), and NASA's EOS Clearinghouse (ECHO, http://www.echo.eos.nasa.gov/) have been developed to facilitate the discovery of the services. The services and catalogs provide interoperable accessibility to existing earth observations and model simulations, such as the Global Mosaic WMS service based on TM images (http://onearth.jpl. nasa.gov/). Geospatial interoperability can help to leverage and link these catalogs, and to chain services (Alameh 2003) together within a larger Service-Oriented Architecture (SOA, W3C 2003). Therefore, the services can be built once and used many times to increase the return on investments and reduce time for prototyping through interoperability (Bambacus and Reichardt 2006). …