Publishing And Federating Global Water Data And Maps Via Web Services

Finding and accessing data in most countries of the world about local, regional and national water resources (streamflow discharge, gauge depth, soil moisture, etc.) has been complicated by a number of issues, from concerns of local and national security, to lack of suitable conventions and standards for data exchange that could be reasonably implemented and enforced at the national and international levels. These issues are now starting to be addressed, thanks to recently adopted standards for hydrologic data exchange, and growing acceptance of community standards for web services to perform such data exchange. This presentation reviews recent work in this area, in particular from an international initiative for the Global Earth Observation System of Systems (GEOSS) to federate regional water data into national pictures for Italy, New Zealand, Canada, and a growing number of countries in Latin America. This builds on previous similar work by the Consortium of Universities for Advancement of Hydrologic Science (CUAHSI) with the U.S. Geological Survey and several other U.S. national agencies. The ability to discover and access such important data should improve the awareness and responsiveness of policy- and decision-makers in the event of natural disasters from storms, flooding and drought

Harmonization - Towards A Standardized River Geometry Format

RiverML is a proposed language for conveying a description of river channel and floodplain geometry and flow characteristics through the internet in a standardized way, which is currently in the early stages of development. RiverML is a joint effort between the CUAHSI HydroShare development team, the World Meteorological Organization (WMO) / Open Geospatial Consortium (OGC) Hydrology Domain Working Group, and an international community of data providers, data users, and software developers. In order to create a standard that will serve the needs of the international hydrologic community, a harmonization effort of three forms of data is presented. First, relevant initiatives from public and private agencies around the world at the international, national, and regional levels are identified. Second, the input requirements and naming conventions for a collection of both design and research-oriented hydraulic software packages are compared. Third, the advantages and limitations of existing transfer formats are investigated. From these data, the goals of an international standard for river geometry are formulated as a set of use cases. The commonalities between existing workflows are used to establish the key information content which a standard format should convey. Finally, recommendations for the functional form and anticipated challenges to development are described

Studying soil moisture at a national level through statistical analysis of NASA NLDAS data

The purpose of this research is to enable better understanding of current environmental conditions through the relations of environmental variables to the historical record. Our approach is to organize and visualize land surface model (LSM) outputs and statistics in a web application, using the latest technologies in geographic information systems (GISs), web services, and cloud computing. The North American Land Data Assimilation System (NLDAS-2) (http://ldas.gsfc.nasa.gov/nldas/; Documentation: ftp://hydro1.sci.gsfc.nasa.gov/data/s4pa/NLDAS/README.NLDAS2.pdf) drives four LSM (e.g., Noah) (http://ldas.gsfc.nasa.gov/nldas/NLDAS2model.php) that simulate a suite of states and fluxes for central North America. The NLDAS-2 model output is accessible via multiple methods, designed to handle the outputs as time-step arrays. To facilitate data access as time series, selected NLDAS-Noah variables have been replicated byNASA as point-location files. These time series filesor 'data rods' are accessible through web services. In this research, 35-year historical daily cumulative distribution functions (CDFs) are constructed using the data rods for the top-meter soil moisture variable. The statistical data are stored in and served from the cloud. The latest values in the Noah model are compared with the CDFs and displayed in a web application. Two case studies illustrate the utility of this approach: the 2011 Texas drought, and the 31 October 2013 flash flood in Austin, Texas

GEOSS AIP And GEOSS Water Services

The Global Earth Observation System of Systems (GEOSS) is being built through the coordination of efforts within the international Group on Earth Observations (GEO), a voluntary partnership established in February 2005, comprised of 89 Member States, the European Commission and 77 Participating Organizations. GEOSS is a global, distributed system accessible through the GEOSS Portal, including satellite observation systems and in situ networks and systems, which will deliver the benefits of Earth observations to both data & information providers and consumers world wide. The 10-Year Implementation Plan defines a vision statement for GEOSS, its purpose and scope, expected benefits for nine “Societal Benefit Areas” (SBAs) (disasters, health, energy, climate, water, weather, ecosystems, agriculture and biodiversity), technical and capacity building priorities, and the GEO governance structure. [1] The GEOSS Architecture Implementation Pilot (AIP) develops and deploys new process and infrastructure components for the GEOSS Common Infrastructure (GCI) as well as for the broader GEOSS architecture. The requirements for AIPs are based on user needs and community scenario requirements. The AIP process aims to increase the use of GEOSS resources by end-users in applying both in situ and remotely sensed data, and by extending results from previous GEO developments through integration with the GEOSS Common Infrastructure (GCI)

GIS/LIS'95 Conference Proceedings, Nashville TN, November 1995. American Society of Photogrammetry and Remote Sensing, Bethesda MD, pp.1-10.

This paper presents an approach for supporting reactive capability in an objectoriented GIS database, through the use of an event interface comprising an event generator and rule objects. This interface supports specification of events spanning sets of geographic-feature objects, and detection of primitive and complex events. Rules can be specified to apply either at a class level (i.e., to all instances of a given geographicfeature class) or at an instance level. In addition we allow evaluation of both pre- and post-conditions on changes to a feature. This approach is relevant in three distinct situations: (1) immediate mode, to execute rules immediately before or after some state change; (2) deferred mode, to execute rules at the end of several changes; and (3) detached mode, to perform rule-based actions separately from the state changes. GIS presents a rich set of problems for which this approach can be useful. This paper outlines the key elements of the rule-based approach employ..