CODATA, and International Activities
The mission of the Committee on Data for Science and Technology (CODATA), established by the International Council for Science (ICSU), is to strengthen international science for the benefit of society by promoting improved scientific and technical data management and use. An overview of CODATA and its international activities in promoting informatics collaborations and projects will be presented, as well as some highlights from the 21st International CODATA conference, held in Kyiv, Ukraine in October 2008.
overage Access Services for Earth and Space Sciences: Requirements Analysis
This presentation will briefly discuss the different perspectives that characterize the main geo-spatial Communities as far as the coverage data model is concerned. Then, it will present the results of a user requirements analysis for an effective coverage access service conceived to serve the use scenarios of the Earth and Space Science Community. Eventually, possible new categories of access services are described comparing them with the existing service implementations. The coverage concept was defined by the ISO 19123 to summarise the different conceptual and physical representations of an image, going further by enlarging the variety of geospatial information that can be represented this way. In fact, a coverage is a feature that has multiple values for each attribute type, where each direct position within the geometric representation of the feature has a single value for each attribute type. The coverage concept generalizes and extends the raster structure type by referring to any data representation that assigns values directly to spatial positions -regularly and non-regularly distributed. In fact, a coverage associates a position within a domain (commonly, spatial-temporal domain) to a value of a defined data type. Hence, it realizes a function (namely, coverage function) from a domain to an attribute domain -i.e. the co- domain or coverage range. Just as the concepts of discrete and continuous phenomena are not mutually exclusive, their representations as discrete features or coverages are not mutually exclusive. The same phenomenon may be represented as either a discrete feature or a coverage. However, coverages are the prevailing data structures in Earth and Space Science community. The analysis of software requirements for coverage access services was made adopting two methods concurrently the Critical Success Factor (CSF) analysis method, which was supplemented by the Usage Cases analysis. This methodology was chosen by the W3C for the Web Services Architecture analysis. The CSF Analysis methodology is a top-down means of determining requirements based on the needs of the organization while the Use Case approach implements a bottom-up methodology collecting users' requirements. The respective results were cross-referenced to ensure consistency. The vast majority of use cases are taken from the work of the OGC GALEON Working Group in the coverage domain. Mainly, GALEON use cases are stemming from the meteo-ocean community, or Fluid Earth Science (FES); however, they appear to cover most of the requirements characterizing the overall Earth and Space Science community.
Serving Collections of Non-gridded Data as Coverages
A particularly interesting outcome of Phase 1 of the OGC (Open Geospatial Consortium) GALEON (Geo-
interface for Air Land Environment Oceans NetCDF) Interoperability Experiment is that a relatively simple
scenario proves to be remarkably useful in a number of settings. From a user perspective, this fundamental
use case consists of the following interaction for requesting data: specify 3D bounding box centered on an
area of interest, specify time frame of interest (e.g., a periods of severe storms, request observed and/or
forecast atmospheric parameter values in the specified space time bounding box. In GALEON 1, the WCS
(Web Coverage Service) specification worked well for serving gridded data from forecast model output and
some satellite imagery -- encoded as netCDF conforming to CF (Climate and Forecast) conventions. But there
is a wealth of data that falls outside the realm of the regularly gridded coverages type that WCS supports at this
time. Station observations and radar scans are just two of the many common examples of non-gridded
collections that can't be served by the current WCS specification. This situation begs the question of what
protocol should be used to deliver collections of non-gridded data. The OGC WFS (Web Feature Service) is
specifically set up for access to traditional "features" that included non-gridded forms of data. The SOS (Sensor
Observation Service) on the other hand is geared toward serving streams of observational data from a wide
variety of sensors. But neither WFS nor SOS has a straightforward mechanism that enables the basic request
for collections of data within a space-time bounding box. In contrast to the current restricted WCS coverage
definition, the ISO concept of a coverage (defined in ISO 19123) is very general and includes both continuous
and discrete coverages. So, at this abstract level, collections of data of the sort discussed here fit into the
general concept of a coverage. Likewise, the OGC O&M (Observations and Measurements) specification
includes collections of observational data as coverages. This presentation examines these issues in terms of
a few specific meteorological data types, cites literature that maps these types to the abstract coverage data
models of ISO and O&M, and develops a strategy for expanding the coverage types served via WCS as a
means of satisfying the simple space-time bounding box request for collections of non-gridded data. With a
little luck by the time of the presentation, there will be working examples of the delivery of such non-gridded
data collections as CF-netCDF objects via a slightly augmented WCS specification.
NASA's Standards Process for Earth Science Data Systems
NASA's Standards Process Group (SPG) facilitates the approval of proposed standards that have proven implementation and operational benefit for use in NASA's Earth science data systems. After some initial experience in approving proposed standards, the SPG has tailored its Standards Process to remove redundant reviews to shorten the review process. We will discuss real examples of the different types of candidate standards that have been proposed and endorsed (i.e. OPeNDAP's Data Access Protocol, Open Geospatial Consortium's Web Map Server, the Hierarchical Data Format, the netCDF Classic Model, Global Change Master Directory's Directory Interchange Format). The Standards Process can accelerate the evolution of practices through better communication from successful practice in a specific community to broader community adoption to community-recognized standards. For each endorsed standard, the availability of high quality documentation for the standard, available reusable software, and information about successful operational experience with the use of the standard will help bridge the chasm from innovative use by visionary practitioners to more popular use by pragmatic users. As an internal working group, the SPG has a NASA agency centered focus. At the same time, there is growing awareness that interagency and international standards are extremely relevant to addressing the regional and global science and decision support applications. The Global Earth Observing System of Systems (GEOSS) Architecture and Data Management (AMD) Standards Interoperability Forum (SIF) is designed to encourage the use of standards in contributed components. It is clear that some of the standards endorsed by the NASA SPG could be important contributions to the GEOSS. The GEOSS recognized standards can also be reviewed as 'defacto' standards by the SPG. NASA stakeholders are often also NOAA stakeholders. Members of the NASA SPG have been working with members of the NOAA standards endorsement process to provide mutual benefit. We will also discuss the role of the NASA SPG participation with these and other cross-agency and international standards initiatives.
NOAA's NPOESS Data Exploitation Project
The U.S. National Oceanic and Atmospheric Administration's NPOESS Data Exploitation (NDE) Project is
building a near-real time processing and distribution system for data from the National Polar-orbiting
Operational Environmental Satellite System (NPOESS) and its forerunner, NASA's NPOESS Preparatory Project
(NPP). The NDE Project has diverse user requirements for atmospheric, oceanographic, and land surface
data products with strict operational timeliness. The NDE Project worked with stakeholders to promote and
adopt widely used scientific data formats consistent with interoperability objectives for the Global Earth
Observation System of Systems (GEOSS). The NDE system was designed to meet these user requirements in
a Service Oriented Architecture (SOA) with product algorithms and product tailoring tools presented as internal
service components. This approach provides scalability and high availability for mission critical operations,
while maintaining flexibility for future products and satellite data processing and distribution requirements.
Report on GIS in Weather, Climate and Impacts Community Workshop
Society and climate are coevolving in a manner that could place more vulnerable populations at risk from exposure to weather and climate stresses. Understanding risks and vulnerabilities to weather hazards and climate change requires interdisciplinary approach, that includes information about weather, climate, natural and built environment and social processes and characteristics. In October 2008, NCAR hosted 3rd Community Workshop on GIS in Weather, Climate and Impacts. The workshop brought together leading researchers and practitioners from multiple disciplines to discuss visions, challenges, and research needs in spatial integration of information from social, atmospheric and related sciences. Workshop discussions focused on 1) atmospheric data needs for spatial societal research and applications, 2) social science data needs for integrative assessments and Earth System modeling and 3) research directions and methodologies for integration of natural and social sciences for weather hazards preparedness and climate change adaptation. In this presentation, key workshop outcomes and future directions in GIS in Weather, Climate and Impacts will be discussed.
Reconnaissance Imaging Spectrometer for Mars CRISM Data Analysis