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Table of Contents:

OF 2004-1014

Disc Contents

Geologic
    Discussion

Data/GIS

• Getting Started

• Navigation

• Seismic-reflection

• Sidescan-sonar mosaics

• Ground-Truthing

Metadata/Data
    Catalog

References Cited

Contacts

Ground-Truthing

Ground-truthing of geophysical data collected in John Day Reservoir was conducted in two stages. These data are available in the data/samples directory, with links to the various data at the bottom of this page, or from the metadata/data catalog page. The first stage was conducted in 2000, immediately following the geophysical surveying. This portion of the work employed the SeaBOSS sampling system (Blackwood and Parolski, 2001) . The SeaBOSS system is equipped with a Van Veen grab sampler, still camera, and video camera. An ESRI point shapefile is provided which indicates the locations where bottom images were taken from the video. The time present in the lower right corner of these images reflects video time (amount of time recorded on video tape) and not local or UTC time. In most cases, the image grabbed was close to the time of a grab sample, but there were times when the video at the time of the grab sample was not good. Thus, in some cases, there is as much as a few minutes difference in time between the image and attempted sample location. Although the SeaBOSS system includes a sampling device, the sample locations and analyses are not provided here, but will be available in a later publication. An ESRI polyline shapefile is provided indicating tracklines along which bottom video information was collected.

In 2002, ground truthing was carried out using a sampler and video system developed by the USGS Biological Resources Division in Cook, Washington. The only navigation made available from this work is the location of sediment samples. A point shapefile is provided indicating these locations. The video was viewed for each sampling transect and a still photo was taken of the monitor displaying the video. These images are not from the exact location of the sediment samples. However, the video transects on this cruise were quite short, so the offset between sample location and image location is assumed to be minimal. In some cases the video was not turned on or did not work properly, therefore not all sample locations have an associated image. Apparent missing station location numbers indicate a station where no grab sample was obtained. The attributes of the ESRI shapefile contain sediment analysis information in addition to other pertinent information related to the sample location.

In both years of ground-truthing, the point shapefiles are setup for hotlinking to the bottom image. Using the provided ArcView project file (johnday.apr), clicking on a point with the lightning bolt tool () will bring up a JPEG image of a bottom photograph associated with that location. In many cases the quality of the image is poor, but is the best available image for that location.

ESRI Shapefiles and JPEG images:

Download zip files:

2000 ground-truthing: polyline shapefile of video tracklines, point shapefile of still photos, bottom images

2002 ground-truthing: point shapefile of bottom images and analysis information, bottom images