What is the Coastal and Marine Geoscience Data System
The Coastal and Marine Geoscience Data System (CMGDS) is the single point of access for all geoscience data published by the U.S. Geological Survey Coastal and Marine Geology Program (CMGP). The goal of this site is to provide a single site where the USGS CMGP data can be found.
How can I use this resource?
This site can be used in two different ways: data discovery and data access. The data access section provides links to the various ways of getting the data. This includes direct data download and a variety of web services that provide direct data access. Data discovery can be done locally by a single user or the site can be harvested by other metadata collections systems for searching using other methods. The headings of each top level bullet below represent the various methods available for discovery or access. Any links in these headings will direct you to that particular function. This site can also be accessed by other programs that are capable of using our information for metadata search or GIS display. The secondary level of bullets describe the urls that are required for use in other programs. They are not linked here as the results have no meaning unless they are utilized by other programs. The Capabilities Documents and such are linked. They will display an XML file that is used by these programs as well.
What data can I expect to find here?
The current data collection includes multi channel seismics, single channel seismics, bathymetry, and sidescan sonar.
Where do these datasets come from?
All datasets come from USGS publications. These publications are generally in the form of data releases with the data included as part of the publication.
What geographic areas do these datasets cover?
Most data results from scientific research in the coastal and offshore areas of United States, and other US territories; and in many lakes and rivers. You can see our data coverage on our global map page or our research field locations.
What are metadata?
Metadata is "data about data." It provides structured information that describes the data it is associated with. This description gives the who, what, when, where, why and how of the data being described. USGS uses the FGDC metadata format standard for all of its data. These metadata records are included in the USGS publications and are linked to from this site to provide greater details about the data being provided.
What are the terms and conditions of data use?
Most U.S. Geological Survey (USGS) information resides in the public domain and may be used without restriction. When using information from USGS information products, publications, or Web sites, we ask that proper credit be given. Acknowledging or crediting the USGS as an information source can be provided by including a line of text citation.
What is GeoMapApp and Virtual Ocean?
Both programs are Java™ applications, which permit dynamic exploration of data from a map interface and the capability to generate custom grids and maps (color, contour, shading, sun illumination). GeoMapApp is a 2D visualization tool for seismic data. Virtual Ocean is a 3D visualization tool for seismic data.
How do I load the datasets into GeoMapApp?
To access the seismic data in GeoMapApp from the top menu choose Portals>Digital Seismic Reflection Profiles then in the right panel choose USGS MCS (multichannel seismic) or USGS SCS (single channel seismic). Either select an expedition or click on a box to zoom to that dataset. It can be difficult to select the inner boxes which is why we created the field activity map in CMGDS so you can figure out the field activity id (expedition) and select it from the expedition list. Then click on a line and then click on load view 1 or 2. The tools above the profiles are pretty self explanatory (zoom in out, flip, expand contract etc). After you have loaded a profile the map will show red were the profile is being displayed. If the profile is larger then the display the portion of the line not displayed will be yellow. If you move the mouse over the loaded profile the curser on the map will show where you are on the map. There are markers and labels for where lines intersect. Click on a tool and then do the action like zoom in zoom out, the hand to move, and the pointer to select. Full instructions for using this program can be found here.
How do I access the datasets through web services in Virtual Ocean?
To access the data in Virtual Ocean the path is the same Portals>Digital Seismic Reflection Profiles then in the right panel choose USGS MCS or USGS SCS. You can load the profiles the same as in GeoMapApp. However Virtual Ocean also allows you to load the profiles as fence diagrams on top of the map. To do this choose a cruise by either method described above, click on box or select expedition. Click on a line or several. They should turn red and white. Then click and hold the right mouse button and drag it toward you and you will tilt the globe. Hold the right button down and move right or left to move in those directions. You can then zoom in with the mouse scroll ball. The default screen hides some of the fence diagram controls so detach the table and see all the controls. For most the Base Seconds will need to change to reflect the record length. Hint if you aren’t seeing anything that looks like real data chances are your Base Seconds are too small. Typing n will orient you back to north and r will put you back into map view or directly vertical.
