Exploring USGS Coastal and Marine Geophysical Data Using GeoMapApp and Virtual Ocean: Tools for Integrating Earth-Science Data

By Shawn Dadisman and Greg Miller May / June 2012

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A new National Ocean Policy has raised awareness about the need to find new and improved ways to share information about the coastal and marine environment with a wide-ranging public audience (http://www.whitehouse.gov/administration/eop/oceans/policy). The U.S. Geological Survey (USGS) Coastal and Marine Geology Program (CMGP) has begun a large-scale effort to incorporate the program’s publicly available, digital geophysical data into two widely used Earth-science tools, GeoMapApp and Virtual Ocean. This task of the CMGP Integrated Data Management System project will help support information exchange with partners, regional planning groups, and the public, as well as facilitate integrated spatial-data analysis. Sharing USGS-CMGP geophysical data via GeoMapApp and Virtual Ocean will aid data discovery and enable the data to support new purposes beyond those for which the data were originally intended.

Above: Three-dimensional (3D) viewing is one of Virtual Ocean's unique capabilities. Here, Virtual Ocean shows a 3D fence diagram created with four USGS multichannel seismic-reflection profiles collected across the continental margin off the Golden Gate (the entrance to San Francisco Bay, California). The fence-diagram mode superimposes the sections onto the Marine Geoscience Data System's Global Multi-Resolution Topography (GMRT) database from LDEO (http://www.marine-geo.org/portals/gmrt/). The user can manipulate the vertical exaggeration, the viewing direction, or the perspective of the data with simple mouse movements. View is south-southeastward, with a topographic vertical exaggeration of 5x. Black lines draped on seafloor show locations of other seismic profiles. Vertical black lines represent course changes, red lines indicate top of profile, and white boundary lines display extent of multichannel surveys. Virtual Ocean's display is highly interactive and allows the user to rotate the image in all directions and turn profiles on or off. [larger version]

Although few open-source tools currently exist for visualizing or analyzing marine geophysical data, GeoMapApp and Virtual Ocean are freely available and well known among the Earth-science community. These applications, which work on multiple platforms (Mac OS X, Windows, and Unix), were specifically developed for exploring Earth-science data collected in the marine environment. The applications are widely used by federal, state, academic, and international Earth-science organizations to view, integrate and explore data in a wide variety of ways in both two-dimensional (GeoMapApp) and three-dimensional (Virtual Ocean) space.

GeoMapApp and Virtual Ocean were developed as part of the Marine Geoscience Data System (MGDS) funded by the National Science Foundation (NSF), with additional support from the Lamont-Doherty Earth Observatory (LDEO) at Columbia University. Virtual Ocean also uses the World Wind 3D engine developed by the National Aeronautics and Space Administration (NASA). LDEO Adjunct Professor Emeritus William Ryan and the rest of the LDEO team have been instrumental in redesigning software to accommodate USGS geophysical resources. In addition to providing access to data holdings within GeoMapApp and Virtual Ocean, both applications allow data to be integrated with information from local or published sources via Open Geospatial Consortium (OGC) standards (http://www.opengeospatial.org/standards/), including Web Map Service (WMS) and Web Feature Service (WFS). Tables, spreadsheets, and various other data import formats are supported, depending on which tool is used. Inclusion of CMGP data in these popular applications will make CMGP geophysical data more accessible and allow integration with many other types of information from both national and international sources.

Above: Table of dropdown menu items from GeoMapApp, showing the wide spectrum of data holdings from national and international sources that are accessible for use in data integration and visualization. For example, to view USGS single-channel and multichannel seismic-reflection datasets, select Digital Seismic Reflection Profiles in the Portals dropdown menu; and to view USGS GLORIA (Geological LOng-Range Inclined Asdic) imagery, select Regional Grids > Backscatter > U.S. Continental Margin in the Basemaps dropdown menu. Additional USGS data types will be available in the future. Virtual Ocean has similar but more limited dropdown menus. [larger version]

Above: GeoMapApp images integrating seismic-reflection data and core information. A, GeoMapApp allows the user to interactively view seismic-reflection data in both map and profile views. Map view (top) shows locations of USGS single-channel chirp seismic-reflection tracklines (black, red, and yellow lines) and USGS core or sample locations (gray dots) off northern Massachusetts. Profile view (below map) shows images of two seismic profiles highlighted on the map view by yellow and red lines. The red segments of the lines show the visible extents of the profiles, and the yellow segments represent portions of the profiles not displayed in the images. The user can manipulate the direction, size, and extent of profiles, as well as add interpretations, export results, and see where profiles intersect (blue vertical lines in profiles). The white box outlines the extent of the selected seismic survey, and the black box indicates the extent of another seismic survey. B, Alternative GeoMapApp table display for the same map view above, but here displaying the USGS core data. Core location highlighted in red on the map corresponds to the table entry highlighted in blue. The data link (first column in table) leads to an online core description. [larger version]

Above: GeoMapApp images demonstrating the ease and value of integrating various data types. A, GeoMapApp presentation of USGS GLORIA sidescan-sonar data collected off the U.S. west coast. The GLORIA data are superimposed on the Marine Geoscience Data System's GMRT. B, GLORIA imagery integrated with NOAA magnetic anomalies (blue, green, and purple stripes at 50-percent opacity), USGS earthquake data (green and yellow dots), and onshore geologic-map information. Interpretations of major tectonic-plate boundaries along the U.S. west coast are shown in yellow. [larger version]

Incorporating USGS data into GeoMapApp and Virtual Ocean has led to the development of the USGS Coastal and Marine Geoscience Data System (CMGDS), a task headed by USGS scientist Greg Miller. The CMGDS is a single point of access to the data (see related article, “Coastal and Marine Geoscience Data System…,” this issue. Datasets must be published before they can be included in any of these public resources. Analyzing the geophysical data holdings for review and reprocessing has provided valuable opportunities for quality control and has helped resolve previously undetected data-management issues.

All three CMGP science centers (in Woods Hole, Massachusetts; St. Petersburg, Florida; and Santa Cruz and Menlo Park, California) have initially focused on importing the vast holdings of single-channel and multichannel seismic-reflection data into GeoMapApp and Virtual Ocean. Currently, data from 161 single-channel and 36 multichannel expeditions have been imported. Project Task Leader Shawn Dadisman has overseen processing performed by Arnell Forde and Karynna Calderon on data collected by the St. Petersburg Coastal and Marine Science Center (SPCMSC), and Dave Foster has led similar work being completed by Jeff Obelcz on data collected by the Woods Hole Coastal and Marine Science Center (WHCMSC). Ray Sliter, Dave Foster, and Shawn Dadisman have coordinated work by Jeff Obelcz and Karynna Calderon on data holdings of the Pacific Coastal and Marine Science Center (PCMSC). The CMGP has one of the nation’s largest collections of publicly available marine seismic-reflection data; once the data are incorporated into GeoMapApp and Virtual Ocean, the number of datasets previously available via these tools will triple. The initial focus has been on data collected by the USGS, but the effort will also include older two-dimensional multichannel datasets that were collected by the petroleum industry and rescued by the USGS (http://walrus.wr.usgs.gov/NAMSS/).

Heather Schreppel (SPCMSC), Carolyn Degnan (PCMSC), and Dan Metzer (National Oceanic and Atmospheric Administration [NOAA]) are working together to address reformatting and publishing of the large holdings of CMGP gravity, magnetic, and single-beam bathymetric data so that these data also can be imported into GeoMapApp and Virtual Ocean, as well as into the National Geophysical Data Center (NGDC) Web site. John O’Malley (WHCMSC) has made GLORIA (Geological LOng-Range Inclined Asdic) sidescan-sonar imagery from all 46 USGS GLORIA cruises available in GeoMapApp via WMS. Plans are also in place to provide access to CMGP swath bathymetry, additional sidescan-sonar mosaics, and lidar (light detection and ranging) data through GeoMapApp and, possibly, Virtual Ocean.

The CMGP Integrated Data Management System project is working to provide these valuable holdings to a broad range of users, including other government agencies and academic institutions involved in planning offshore activities, managing natural resources, and identifying gaps in data and knowledge when planning future data collection. Access to USGS information through these systems will also facilitate new research and discoveries as the data are used in new and different ways.

The GeoMapApp and Virtual Ocean software can be downloaded from http://www.geomapapp.org/ and http://www.virtualocean.org/, respectively. USGS data loaded into GeoMapApp and Virtual Ocean are available for download via the Coastal and Marine Geoscience Data System (CMGDS; http://cmgds.marine.usgs.gov/).

Coastal and Marine Geoscience Data System—Single Point of Access for Digital Geophysical and Lidar Data of the USGS Coastal and Marine Geology Program May / June 2012

Coastal and Marine Geoscience Data System USGS

National Archive of Marine Seismic Surveys (NAMSS) USGS

National Ocean Policy U.S. Government

GeoMapApp Columbia University

Virtual Ocean Columbia University

Marine Geoscience Data System Columbia University

Global Multi-Resolution Topography (GMRT) Columbia University

OGC Standards Open Geospatial Consortium

National Geophysical Data Center (NGDC) NOAA

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May / June 2012

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in this issue:

cover story:
Gas Hydrates and Climate Warming

Real-Time Mapping of Methane Concentrations

Coastal and Marine Geoscience Data System

Exploring Geophysical Data Using GeoMapApp and Virtual Ocean

Weather Prevents Survey of California Sea Otter Population

Exhibit Will Celebrate Collaboration Between Artists and Scientists

Antarctic Science and Arts

USGS Scientists Selected as Fellows of the American Geophysical Union

Chinese Scientist Visiting USGS Pacific Coastal and Marine Science Center

Belgian Volunteer Assists Staff in Everglades National Park

May / June 2012 Publications