THE GEON IDV (INTEGRATED DATA VIEWER) FOR DATA INTEGRATION AND EXPLORATION IN THE GEOSCIENCES

The GEON IDV, provided and developed in part by UNAVCO, is a freely-available 4D software tool for data visualization and exploration in the earth sciences. New complex data sets require a tool with full 3D and temporal display capabilities to discover and interpret details in the data. Most any earth-mapped data, including data with depth extent below or above the surface, can be seen in the IDV. The IDV can show data for any area on the earth, any map projection, and any vertical scale, with time animation controls.

The GEON IDV (called the IDV here) was designed to enable data integration, and to foster inter-interoperability across the earth sciences. Diverse data sets from various distributed data sources can be viewed simultaneously in the same display. For example, the IDV can simultaneously display seismicity under St. Augustine volcano (Alaska) using data from real-time earthquake catalogs, and real-time 3D images of atmospheric ash clouds over the volcano, using from U.S. National Weather Service WSR88D Level II radar data, in true vertical scale, with a 3D surface relief image.

The IDV recognizes several data source protocols, including local files, URLs, web catalog servers such as THREDDS catalogs and OPeNDAP data servers, web map server, and RSS feeds (such as the USGS “this week's earthquakes”). Catalogs need not be located at physical data locations, offering the possibility of distributed data sources, data services, and data users.

The IDV can be a key part of a web-based data store and provision service. As an example, IRIS has recently built a web portal to their catalog of earthquake epicenter locations and magnitudes. The user can specify earthquakes of interest by latitude, longitude, time, and magnitude range. The IRIS service generates a file with the data and provides the URL to the file. The IDV can use this service and URL as a data source. IRIS is now considering a web service to convert seismic tomography data files, submitted online by their creators, for conversion to a format the IDV can use.

The IDV can be scripted to run unattended and make data display imagery, for example, on time as new data arrives, or on demand from a web site. This allows a web site to provide images of IDV displays of data specified by an online user. The web service running the IDV need not be co-located with the data source.

The IDV relies on the power of the NetCDF file format, which stores multi-dimensional data, related metadata, and source information. NetCDF data files provide complete metadata, including geolocation, data units and scaling, time values and formats, variable descriptions, data provenance, publication references, data creator credits, affiliations, contact information, and information to support data discovery by geospatial, temporal, and keyword searches. All netCDF metadata is available in the IDV. The IRIS tomography data format converter will convert ASCII files of tomography data to NetCDF files.

The UNAVCO GEON web site ( http://geon.unavco.org/unavco/ ) provides a complete description of the GEON IDV, including how to download the software, a tutorial, help, and detailed guides to formatting data for the GEON and software tools for data conversion to netCDF.

The UNAVCO portion of this work is funded by the NSF Division of Earth Science through the GEON Information Technology Research project. We thank the science investigators, including Mike Ritzwoller, Nikolai Shapiro, Alan McNamara, Francis Wu, Corne Kreemer, Bill Holt, Bob Smith and Greg Waite, and the USGS for sharing their results and providing us with valuable feedback.

IDV oblique view of the geophysics of the Yellowstone National Park area, including 3D surface relief, GPS velocity vectors(magenta), surface fault lines (green), caldera outline (red), epicentral focal mechanisms, and an isosurface of low P-wave velocity.