Digital seafloor images and sediment grain size from the mouth of the Columbia River, Oregon and Washington, 2014
This dataset includes 2,523 still images extracted from geo-referenced digital video imagery of the seafloor at the mouth of the Columbia River, OR and WA, USA, along with grain size analysis of the surface sediment. Underwater digital video was collected in September 2014 in the mouth of the Columbia River, USA, as part of the U.S. Geological Survey Coastal and Marine Geology Program contribution to the Office of Naval Research funded River and Inlets Dynamics experiment (RIVET II). Still images were extracted from the underwater video footage whenever the camera was resting on the sediment bed and individual sediment grains were visible and in focus. The images are used to calculate the median grain size through an auto-correlation method (Barnard and other 2007), and are provided in an accompanying .csv file.
Gelfenbaum, Guy R., Carlson, Emily M., Stevens, Andrew W., and Rubin, Dave M., 2017, Digital seafloor images and sediment grain size from the mouth of the Columbia River, Oregon and Washington, 2014: data release DOI:10.5066/F7K64G8V, U.S. Geological Survey, Coastal and Marine Geology Program, Pacific Coastal and Marine Science Center, Santa Cruz, California.
What coordinate system is used to represent geographic features?
Horizontal positions are specified in geographic coordinates, that is, latitude and longitude.
Latitudes are given to the nearest 1.0E-6.
Longitudes are given to the nearest 1.0E-6.
Latitude and longitude values are specified in Decimal degrees.
The horizontal datum used is WGS1984.
The ellipsoid used is WGS1984.
The semi-major axis of the ellipsoid used is 6378137.0.
The flattening of the ellipsoid used is 1/298.257223563.
The entity and attribute information provided here describes the tabular data associated with the images in the dataset. Please review the detailed descriptions that are provided (the individual attribute descriptions) for information on the values that appear as fields/table entries of the dataset.
The entity and attribute information was generated by the individual and/or agency identified as the originator of the dataset. Please review the rest of the metadata record for additional details and information.
Video footage was converted from video type .MXF to a Red Hen System compatable format of .AVI using the software Acrok MXF Converter. All image and sound quality were maintained at the original video's quality.
Date: 12-Jun-2015 (process 2 of 6)
Video footage was indexed using Red Hen System's proprietary software IsWhere. An XML format metadata file was produced from each video and includes GPS information intermittently through the video of: latitude (decimal degrees), longitude (decimal degrees), GPS altitude (meters), video time (HH:mm:ss:ms), Dublin Julian Date in UTC (julian date = timeCode+2415020), course direction (degrees), speed (meters/second).
Date: 12-Jun-2015 (process 3 of 6)
Geotagged images were grabbed from the video every 0.5 second. From this set of evenly timed images, images were chosen when the sediment bed was in focus and the camera was resting on the bed. This process resulted in there being multiple images for each location. The image files contain the GPS location in lat/lon decimal degrees.
Date: 12-Jun-2015 (process 4 of 6)
Each image is given a file name based on the video it was taken from, followed by the time stamp in the video. For example image "0205301_0_1_41_0" is from video 0205301 at time 00:01:41:00 (HH:mm:ss:ms).
Date: 12-Jun-2015 (process 5 of 6)
The UTC time of each image was calculated by extracting the UTC time at the beginning of the video from the XML file produced by IsWhere for each video file, and adding the time stamp of the image. These values are recorded in Julian time in the UTC time zone in the provided spreadsheet. The lat/lon values were converted to UTM zone 10N, WGS84 coordinates using the matlab tool "deg2utm" version Aug/06, available at mathworks.com, and recorded in the provided spreadsheet.
Date: 12-Jun-2015 (process 6 of 6)
The median grain size of sediment shown in each image was estimated using an auto-correlation process and calibration images, which are available in "child-item title", included with this publication.
Barnard, P.L., Rubin, D.M., Harney, J., and Mustin, N., 2007, Field test comparison of an auto-correlation technique for determining grain size using a digital ‘beachball’ camera versus traditional methods.
Gelfenbaum, G., Finlayson, D., Dartnell, P., Carlson, E., and Stevens, A., 2015, Bathymetry and backscatter from 2013 interferometric swath bathymetry systems survey of Columbia River Mouth, Oregon and Washington.
How well have the observations been checked?
Accuracy of dataset attribute information was deduced to be good based both on visual examination of still images, video imagery, navigation trackline location on agreement with observer's field knowledge.
How accurate are the geographic locations?
The positions of the data reflect the position of the GPS antenna on board the boat when data were collected and not the real location of the camera in the water. Positional data in this report were not corrected for layback and thus represent only approximate locations.
USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey as the originator(s) of the dataset and in products derived from these data. Use of appropriate byline/photo/image credit is requested; Suggested credit: Photo by USGS (or U.S. Geological Survey, depending on audience).
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What's the catalog number I need to order this data set?Digital seafloor images in JPEG format (MCR14_SeafloorSediment_Images.zip) and a table in comma-delimited format containing location and grain size data (MCR14_SeafloorSediment_Grainsize.csv) are available for download, along with CSDGM FGDC-compliant metadata (MCR14_SeafloorSediment_metadata.xml)
Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.
Table containing locations and time of still-image frame grabs taken from underwater video footage, along with grain size estimates of seafloor sediment.
in format CSV
(version Microsoft Excel 2010)