San Diego Supercomputer Center

The Spatial Information Systems Laboratory of San Diego Supercomputer Center, University of California at San Diego, has been working with OGC standards and technologies over many years. OGC standards have been used in several large projects at SDSC. In geology, The Geosciences Network project (GEON) has developed an online portal for registering and integrating user-contributed data and services, including OGC's WMS and WFS services, and KML documents. In a neuroscience project, medical images are served to online clients using WMS. In a Hydrologic Information System (HIS) project, described below, we have been using OGC specifications (in particular: GML, SOS, WFS, WMS, and O&M), and participating in the OGC standards process most thoroughly, by developing an OGC discussion paper focused on Water Markup Language (WaterML) for exchange of hydrologic information, and by working towards harmonizing this encoding with the rest of OGC specifications under the aegis of a recently established Hydrology Domain Working Group (HDWG).

The HIS project has as its mission development of cyber-infrastructure to advance hydrologic research and education. It is supported by the US National Science Foundation, and is conducted under the aegis of the Consortium of Universities for the Advancement of Hydrologic Science, Inc . (CUAHSI), an organisation representing more than 120 universities in the US and abroad. Over the last three years the CUAHSI HIS team, with San Diego Supercomputer Center as the technology partner, has been researching, prototyping and implementing web services for accessing various hydrological data sources, and developing online and desktop applications for storing, managing and exploring hydrological time series and other hydrological data. The HIS design follows the open services-oriented architecture model; that is, it relies on a collection of loosely coupled, self-contained services that communicate with each other and may be called up from multiple clients in a standard fashion. The core of the system is WaterOneFlow web services for uniform access to heterogeneous repositories of hydrological observation data. The services follow a common XML messaging schema named CUAHSI WaterML which includes constructs for transmitting observation values and time series, and observation metadata including information about sites, variables and networks. Many hydrologic data sources are available now via this web service interface, including water quantity and water quality data collected by the United States Geological Survey, US Environmental Protection Agency, other federal and state agencies, and many academic and non-profit research groups.

The WaterML specification is available as an OGC Discussion Paper (document 07-041). The CUAHSI HIS team has been closely working with our OGC partners on harmonising the specification with OGC standards such as GML and Observations and Measurements (05-087) to make the next version of CUAHSI web services OGC-compliant. OGC compliance will dramatically increase their use and facilitate harmonisation with international standards. Recently, a new Hydrology Domain Working Group has been established within OGC, to support this joint development, towards a WaterML 2.0 specification which is expected to integrate the semantics of hydrologic data discovery and access established and community-tested within the CUAHSI HIS project, with the O&M encoding, as a profile of the latter.

We have enjoyed this fruitful collaboration, and look forward to future stimulating and thorough professional exchanges that OGC is known for.

Ilya Zaslavsky
Spatial Information Systems Laboratory,
San Diego Supercomputer Center
University of California at San Diego

 SDSC

For more information, please visit:

http://his.cuahsi.org (main project web site),

and

http://spatial.sdsc.edu (the lab's web site)