About the Data System (Purposes, Audience)
The Environmental Geoweb Service (Geoweb) is a service that locates, indexes, and presents geographically-referenced scientific data so that EPA scientists can perform cross-disciplinary searches for data of relevance to their work, and can publish data from their research that might benefit other scientists. The Geoweb Service has been designed and developed within the EPA and is currently in an early stage of production use.
The Geoweb Server searches for and indexes geographically-referenced scientific data made public on the servers of organizations outside of the EPA, or on selected data servers within the EPA network. The outside sources are currently concentrated at NASA, NOAA, and the Center for Ocean-Land-Atmosphere. The inside sources include Community Mesoscale Air Quality data. The Geoweb Service has the potential to index any geographically-referenced data published on servers inside or outside of the EPA. User connection to search the index is only available from workstations on the EPA internal network.
The Geoweb Server normally performs its dataset indexing at a weekly interval. The Server is instructed to web-crawl an adjustable list of scientific data servers. Metadata about the files found on the indexed servers is brought back to EPA’s Geoweb Server and assembled into an xml database. This database contains all computer-obtainable metadata about each indexed file, and the location of the file on the Internet. The data files themselves remain on the servers where originally published. Currently, about 700,000 scientific files are indexed.
Users of the Geoweb Service connect to it at http://gds.rtpnc.epa.gov. They can follow links to specific data sources found on the home page, or perform searches for data by providing search terms. The searches execute quickly because the metadata being searched is all local to the Geoweb Server. The user is presented with a search results list, similar to Google or Yahoo search results. The user can then view the metadata associated with each dataset, or initiate a visualization of the data contents. The visualizations are performed using the World Wind Geo tool, based on NASA’s World Wind, and developed here at EPA; or by using Google Earth, NASA’s World Wind, or ArcGIS Explorer. The reading of metadata and the visualization of the data correctly referenced to the World Wind, Google Earth, or ArcGIS globe is supported for all data set types. Data served from OPeNDAP servers can also be subsetted by geographic bounding boxes, date, or time and the data subset can then be downloaded across the Internet to the user’s workstation.
List of Publications, Papers, Presentations
Data System Scope
Spatial - Temporal Coverage
Forecasting and Reanalysis
Characterization, Trends, Accountability
Data System IT
Primary/Official Store for Some data
Providing Data Access to users/externals
All of the files indexed by the Geoweb Service provide metadata so that the user can understand the content, and are copied from their source to the user’s workstation when a visualization is requested. The visualization is performed on the user’s workstation within the World Wind Geo tool, within Google Earth, etc.
Some of the files indexed by the Geoweb Service are served by OPeNDAP servers (Open-source Project for a Network Data Access Protocol) operated by NASA, NOAA, etc. Web browsers can work with OPeNDAP servers to identify a subset of the data, based on the variables in the file; and then download just that subset of data to the user’s workstation.
A user of the Geoweb connects to the Server using a web browser such as Firefox or Internet Explorer. This permits searching for data files and viewing of metadata about each file. After a file of interest is located, the data can be visualized on-screen provided that a tool such as World Wind Geo, Google Earth, NASA’s World Wind, or ArcGIS Explorer are installed on the workstation. For a survey of map visualization tools for use within the EPA, see http://intranet.epa.gov/rtpgis/mapvizsvcs.html. The World Wind Geo tool is a free download from http://code.google.com/p/worldwindrcp/. Google Earth Pro is available within the EPA via Agency-wide license. See http://intranet.epa.gov/rtpgis/mapvizsvcs.html for information on obtaining the license. NASA’s World Wind is a free download from http://worldwind.arc.nasa.gov/. ArcGIS Explorer is a free download from http://www.esri.com/software/arcgis/explorer/index.html.
Decision Support (e.g. some integration into user business process)
Other DS Values
Data Access and/or Output Interoperability
Reusable Tools and Methods
Security Barriers and Solutions
As of February, 2008, the Geoweb Service is on the EPA Intranet at http://gds.rtpnc.epa.gov. The Geoweb application is operable in the early stages of production use. A User’s Guide is linked to the home page at the URL above. The User’s Guide includes several two-minute videos illustrating the use of the Geoweb tools. Those outside of the EPA network do not have access.
User Feedback Approach
User Provided Content
The Geoweb application has been sponsored by ORD and developed by OEI/OTOP/NCC’s Center for Environmental Computing (CEC). Mr. Ravi Nair of CEC is the responsible EPA manager.