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Geo-enabling web browsers


By GeoConnexion - 14th May 2014 - 10:49

The OGC’s OpenSearch geo and time extensions encoding standard provides a way for developers to enhance search engines and configure them to query earth science sensor data servers, writes Hervé Caumontâ©

Recent activities in the standards community have significantly lowered this hurdle. Part of these activities, the OGC OpenSearch geo and time extensions encoding standard (OGC OSxGTOOGATEES) specifies how to enhance search engines and configure them to access similarly enhanced sensor data servers, so that users can query resource URLs using combinations of time extents, geographic areas or location names, and likely keywords.â©

This use of the OpenSearch geospatial extensions is intended to complement other metadata search solutions, such as ebRIM and the OGC catalogue services for the web interface standard (CSW). CSW provides the HTTP protocol binding for the OGC catalogue services interface standard, a compressive specification for standard interfaces that enable communication between clients and geospatial catalogue services. OGC OSxGT provides a simpler, ‘mass market’ style interface for publishing and discovering web-resident geospatial data and services.â©
An open source originâ©

OGC OSxGT defines a very simple way to configure OpenSearch for spatial and temporal queries over distributed repositories of contents having geographic and time properties, and for syndication of these search results in one shared index. Using federated search technology, OpenSearch allows users to tap into multiple repositories with a single query.â©

This standards work activity did not originate in the OGC. It began as a project within the OpenSearch community of developers proposed by GeoIQ’s Andrew Turner. In 2009, Terradue submitted OpenSearch Geospatial Extensions as a discussion paper to the OGC, thus codifying in a form compatible with OGC rules the extension that already existed. It was moved in 2010 to the OGC CSW standards working group (SWG), which then issued a motion to adopt the use of OpenSearch as an interface with geospatial and temporal extensions, Atom-encoded responses and a mandatory HTTP binding. After considerable review and then a voting period, that specification is now an OGC adopted standard. â©

This has provided a way to get wider international participation in the specification’s development, testing, promotion, use and maintenance. In 2013, an OGC Technical Committee SWG developed a standard called the OGC EO metadata profile of observations and measurements encoding standard that builds on OGC OSxGT. Moreover, through the OGC’s good relationships with other standards development organisations, OGC OSxGT also now has greater visibility with other standards organisations in the larger standards world and greater visibility in the larger world of web developers and managers of geospatial information resources.â©
Success from strong community buildingâ©

Industry is recognising the potential of OGC OSXGT and vendors are developing tools. “My team and I are actively working in OpenSearch in our roles at ESRI, and interested in collaborating with others using or evolving the specification,” says Andrew Turner, CTO at the ESRI R&D Center.â©

“CubeWerx was an early adopter of OpenSearch technology and is a primary contributor to the OGC OpenSearch Geo and Time extensions standards,” says Peter A Vretanos, CTO and senior developer at CubeWerx. “We have carefully enhanced our OGC-compliant offerings to include support for OpenSearch technology, including the geo and time extensions. This allows OpenSearch clients to easily access our metadata catalogues and data servers. Moving forward, we will continue to enhance existing functionality and developing new product functionality that leverages the power of OGC services and OpenSearch primarily within the imagery and spatial data infrastructure domains.” â©

The community commitment is growing. Overall, the idea is to encourage development of a collection of these tools to cover and progressively generalise both the engineering approach and the functional scope of the tools. This will open up new applications for the exploitation of sensor data.â©

“Terradue is now building ‘data casting’ applications,” says Pedro Gonçalves, CTO at Terradue. “These are produced as custom services for research activities and help a scientist to drill down into distributed catalogues and define a coherent set of data of interest for an experiment.”â©

Deployed on cloud infrastructures, these applications are naturally complemented by data staging tools that can take the final parameters of those results as their input and feed processing chains running on distributed processing clusters. The end result will be much wider and better use of the world’s rapidly growing library of earth observation data.â©

The end result will be much wider and better use of the world’s rapidly growing library of earth observation dataâ©

Hervé Caumont is program manager at Terradue (www.terradue.com) and senior architect of the OGC interoperability program teamâ©

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