0.5-m Stretched Grayscale Image of the Sidescan-Sonar Data From National Oceanic and Atmospheric Administration (NOAA) Survey H11077 of the Sea Floor in the Vicinity of Woods Hole, Massachusetts (H11077_SSS100_GEO.TIF, Geographic)

The sidescan-sonar data were acquired with a Klein T5000 sidescan-sonar system hull mounted to a 29' aluminum launch deployed from the NOAA ship Whiting. The system was set to sweep 100 m to either side of the launch tracks. The system emits port and starboard 50°-wide beams tilted down 20° from horizontal, and transmits at 455 kHz. The data were acquired in XTF (extended Triton data format), recorded digitally through an ISIS data acquisition system, and processed using CARIS SIPS (Sidescan Image Processing) software for quality control, and to produce a composite sidescan-sonar image at 0.5-m horizontal resolution. As part of this process, the sidescan-sonar data were demultiplexed and filtered to remove speckle noise and to correct for slant-range distortions. Image 'shine through', to account for areas of overlap, and auto-contrast adjustment were applied. Tonal artifacts caused by inaccurate across-track normalization present on the sidescan-sonar imagery are minor. Contrast enhancement based on the dynamic range of the data was applied to the mosaic and it was then projected into UTM Zone 19 to produce the final enhanced image.

The image was imported into Adobe Photoshop CS2 in order to apply a linear stretch (i.e., increase the dynamic range of the data) and to invert the grayscale to make strong reflections light tones and weak reflections returns darker tones.

The UTM sidescan-sonar image was projected from UTM Zone 19 NAD83 to geographic WGS 84 using transformation 1 in ArcGIS 9.2 with the ArcToolbox Project Raster Tool.

Within ArcMap 9.2, the Data-Export option (Use Renderer box checked; cell size set to default; TIFF format specified) was used to convert the 16-bit TIFF to an 8-bit TIFF image.

PhotoShop CS was used to convert the black border to white with the Paint Bucket tool and to correct tonal artifacts caused by improper cross-track normalization.

Edits to the metadata were made to fix any errors that MP v 2.9.32 flagged. This is necessary to enable the metadata to be successfully harvested for various data catalogs. In some cases, this meant adding text "Information unavailable" or "Information unavailable from original metadata" for those required fields that were left blank. Other minor edits were probably performed (title, publisher, publication place, etc.). The source information was incomplete and had to be modified to meet the standard. Both geographic and a planar coordinate system were present, the planar one was removed with the resolution transferred to the geographic. The metadata date (but not the metadata creator) was edited to reflect the date of these changes. The metadata available from a harvester may supersede metadata bundled within a download file. Compare the metadata dates to determine which metadata file is most recent.

Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog.

Added keywords section with USGS persistent identifier as theme keyword.