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Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR Neonet A metadata application demonstrating SatCAST Edwin Wisse & Rob van Swol National Aerospace Laboratory CXXX-1A Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR Overview History: Sawa and SatCAST demonstrations Neonet network The software Metadata gathering and distribution Using multicast to distribute metadata Demonstration CXXX-2A Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR 1998: Sawa demonstration Demonstrated IP over satellite & caching, no multicast Application: Neonet version 0 No XML yet: HTML based Built a single site combining and crosslinking pages from different sites about a common theme: remote sensing Site was replicated on different UNEP sites by retrieving databases with HTML files. CXXX-3A Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR 2000: SatCAST demonstration Multicast capability Demonstration application: Neonet version 2 Using structured metadata in XML Network with nodes about different topics in remote sensing Demonstration: – Neonet functionality – Database synchronisation by multicast over satellite link. CXXX-4A Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR Neonet: Background Netherlands Earth Observation Network Allow (Dutch) users of remote sensing data access to information in the Netherlands and abroad. Keep information at the provider Connect to other metadata infrastructures – CEOS IDN – CEO CXXX-5A Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR Neonet nodes A Neonet node is a website with supporting software. A node covers a self-chosen theme in remote sensing Users can search for and enter metadata in a fixed format. Format is derived from the CEO recommendation on metadata. CXXX-6A Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR Neonet network (1) The network is a group of nodes running Neonet software Node maintainer(s) decide what is appropiate information A node servers a user community, example: – atmospheric chemistry – water management Nodes are organised hierarchically General node at top: APEX CXXX-7A Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR Neonet network (2) CXXX-8A Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR Metadata flow Node email Node email Node metadata file Provider Metadata entered at a specialised node is sent automatically to the nodes above. E-mail is available everywhere Even behind firewalls CXXX-9A Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR Neonet software Retrieve metadata from provider by HTTP – Version 0: HTML pages – Version 1: metadata in XML pages (CEO like format) Uses CEO standard for metadata Status: version 2 released october (but used in SatCAST) Available for interested institutes CXXX-10A Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR Software: elements • A Neonet node runs: • Webserver • Database • Servlet package • Java application for database sync and metadata retrieval • Nodes can be installed on systems running Windows and a number of Unix systems (SGI, Solaris, Linux). CXXX-11A Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR SatCAST setup 3 top level nodes with local databases and no sub-nodes Synchronisation: – Nodes synchronise their databases using HTTP requests – Added for SatCAST Multicast aspect: – New or changed XML files get broadcasted to all nodes – Nodes retrieves files and records from local cache – No multicast for servlet results, only for database synchronisation CXXX-12A Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR Synchronisation Node Node admin XML SatCAST Multicast A node exports its database to a set of XML files, so it can be accessed using HTTP admin XML Node CXXX-13A Nationaal Lucht- en Ruimtevaartlaboratorium National Aerospace Laboratory NLR Demonstration Three nodes were set up, all are Apex nodes. Check each other every 10 minutes. Metadata entered at 1 node is found and retrieved by the others No instant result Short demonstration of other Neonet features Questions? CXXX-14A