Metadata: Identification_Information: Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: 2011 Title: GAK_Q52.TIF - Gulf of Alaska U.S. EEZ GLORIA sidescan-sonar data mosaic (22 of 30) (LCC, 50 m, WGS84) Edition: 1.0 Geospatial_Data_Presentation_Form: remote-sensing image Series_Information: Series_Name: Open-File Report Issue_Identification: 2010-1332 Publication_Information: Publication_Place: Pacific Coastal and Marine Science Center, Menlo Park, CA Publisher: U.S. Geological Survey, Coastal and Marine Geology Program Online_Linkage: https://doi.org/10.3133/ofr20101332 Online_Linkage: https://pubs.usgs.gov/of/2010/1332/htmldocs/gak/gak_indexmap.html Online_Linkage: https://pubs.usgs.gov/of/2010/1332/gloria_data/gulf_of_alaska/gak_q52.zip Larger_Work_Citation: Citation_Information: Originator: Valerie F. Paskevich Originator: Florence L. Wong Originator: John J. O'Malley Originator: Andrew J. Stevenson Originator: Christina E. Gutmacher Publication_Date: 2011 Title: GLORIA Sidescan-Sonar Imagery for Parts of the U.S. Exclusive Economic Zone and Adjacent Areas. Edition: 1.0 Series_Information: Series_Name: Open-File Report Issue_Identification: 2010-1332 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: https://pubs.usgs.gov/of/2010/1332/ Description: Abstract: GLORIA data for the Gulf of Alaska Exclusive Economic Zone (EEZ) were acquired during five cruises over a four year period. The first cruise conducted in 1986 (F-1-86-GA) surveyed an area of the north-central mosaic area and covered an area of approximately 40,000 square kilometers (sq km). The second two cruises (F-8-88-AA, F-9-88-WG) were conducted in 1988. One of the 1988 cruises (F-8-88-AA) focused on a survey of the Aleutian Arc. The eastern most portion of that survey extended outside of the Aleutian Arc survey area and covered an area of approximately 52,000 square kilometers (sq km) of seafloor on the western edge of the Gulf of Alaska. The final two cruises (F-6-89-GA, F-7-89-EG) were completed in 1989. As in earlier EEZ reconnaissance surveys, the USGS utilized the GLORIA (Geological LOng-Range Inclined Asdic) sidescan-sonar system to complete the geologic mapping. The collected GLORIA data were processed and digitally mosaicked to produce continuous imagery of the seafloor. Thirty digital mosaics with a 50-meter pixel resolution were completed for the region. Purpose: This remote sensing image of the seafloor is 22 of 30 mosaics created from GLORIA sidescan-sonar data covering the Gulf of Alaska. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 19860624 Ending_Date: 19890710 Currentness_Reference: ground condition with the following date ranges: 19860624 to 19860703, 19880706 to 19880802, 19880805 to 19880831, 19890516 to 19890612 and 19890614 to 19890710 Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -141.156377 East_Bounding_Coordinate: -137.671796 North_Bounding_Coordinate: 59.098902 South_Bounding_Coordinate: 56.895803 Keywords: Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:c68bebfb-e220-42c5-9ea5-810354e37d5e Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Theme_Keyword: Coastal and Marine Geology Program Theme_Keyword: CMGP Theme_Keyword: Western Coastal and Marine Geology Theme_Keyword: WCMG Theme_Keyword: Geological LOng-Range Inclined Asdic Theme_Keyword: GLORIA Theme_Keyword: GeoTIFF image Theme_Keyword: grey scale image Theme_Keyword: backscatter Theme_Keyword: acoustic reflectivity Theme_Keyword: marine geology Theme_Keyword: sidescan-sonar mosaic Theme_Keyword: Exclusive Economic Zone Theme_Keyword: EEZ Theme_Keyword: Infobank identifier F-8-88-AA Theme_Keyword: Infobank identifier F-1-86-GA Theme_Keyword: Infobank identifier F-6-89-GA Theme_Keyword: Infobank identifier F-7-89-EG Theme_Keyword: Infobank identifier F-9-88-WG Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: oceans Theme_Keyword: geoscientificInformation Theme_Keyword: imageryBaseMapsEarthCover Theme: Theme_Keyword_Thesaurus: NASA/Global Change Master Directory (GCMD) Earth Science Keywords, Version 6.0.0.0.0 Theme_Keyword: Oceans > Ocean Acoustics > Acoustic Reflectivity Theme: Theme_Keyword_Thesaurus: NASA/Global Change Master Directory (GCMD) Instrument Keywords Theme_Keyword: ACOUSTIC RECEIVERS Theme_Keyword: GLORIA > Geological Long-Range Inclined ASDIC Theme_Keyword: SIDE-SCAN SONAR Theme: Theme_Keyword_Thesaurus: Data Categories for Marine Planning Theme_Keyword: distributions Theme_Keyword: physical habitats and geomorphology Theme: Theme_Keyword_Thesaurus: Marine Realms Information Bank (MRIB) Keywords Theme_Keyword: seabed Theme_Keyword: Exclusive Economic Zone (EEZ) Theme_Keyword: sidescan sonar Theme_Keyword: marine geophysics Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: sidescan sonar Theme_Keyword: image mosaics Theme_Keyword: marine geophysics Theme_Keyword: sea-floor characteristics Theme_Keyword: sea-floor acoustic reflectivity Theme: Theme_Keyword_Thesaurus: Coastal and Marine Ecological Classification Standard (CMECS) Theme_Keyword: Marine Oceanic Theme_Keyword: Tectonic Trench Theme_Keyword: Abyssal/Submarine Fan Theme_Keyword: Continental/Island Rise Theme_Keyword: Continental/Island Slope Theme_Keyword: Marine Basin Floor Place: Place_Keyword_Thesaurus: None Place_Keyword: Alaska Place_Keyword: Gulf of Alaska Place_Keyword: Aleutian Trench Place_Keyword: Aleutian Abyssal Plain Place_Keyword: Surveyor Channel Place_Keyword: Chirikof Channel Place_Keyword: Kodiak-Bowie seamount chain Place_Keyword: Alaskan Abyssal Plain Place_Keyword: Yakutat Margin Place_Keyword: British Columbia Margin Place_Keyword: Queen Charlotte Fault Place: Place_Keyword_Thesaurus: NASA/Global Change Master Directory (GCMD) Place Keywords Place_Keyword: Ocean > Pacific Ocean Place_Keyword: Ocean > Pacific Ocean > North Pacific Ocean Place_Keyword: Ocean > Pacific Ocean > North Pacific Ocean > Gulf Of Alaska Place: Place_Keyword_Thesaurus: Coastal and Marine Ecological Classification Standard (CMECS) Place_Keyword: Gulf of Alaska Ecoregion Place_Keyword: North American Pacific Fijordland Ecoregion Stratum: Stratum_Keyword_Thesaurus: Coastal and Marine Ecological Classification Standard (CMECS) Stratum_Keyword: Substrate Access_Constraints: None Use_Constraints: Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the dataset. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Florence Wong Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical address Address: 345 Middlefield Road MS 999 City: Menlo Park State_or_Province: CA Postal_Code: 94025 Country: USA Contact_Voice_Telephone: (650) 329-5327 Contact_Facsimile_Telephone: (650) 329-5198 Contact_Electronic_Mail_Address: fwong@usgs.gov Browse_Graphic: Browse_Graphic_File_Name: https://pubs.usgs.gov/of/2010/1332/gloria_data/gulf_of_alaska/browse/gak_q52-thumb.gif Browse_Graphic_File_Description: Thumbnail image showing an overview of the Gulf of Alaska U.S. EEZ GLORIA mosaic 52. Browse_Graphic_File_Type: GIF Browse_Graphic: Browse_Graphic_File_Name: https://pubs.usgs.gov/of/2010/1332/gloria_data/gulf_of_alaska/browse/gak_q52.gif Browse_Graphic_File_Description: Browse image showing an overview of the Gulf of Alaska U.S. EEZ GLORIA mosaic 52. Browse_Graphic_File_Type: GIF Data_Set_Credit: The U.S. Geological Survey (USGS) must be referenced as the originator of the dataset in any future products or research derived from these data. Native_Data_Set_Environment: Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.0.0.535 Cross_Reference: Citation_Information: Originator: J.V. Gardner (editor) Originator: M.E. Field (editor) Originator: D.C. Twichell (editor) Publication_Date: 1996 Title: Geology of the United States Seafloor: The View from GLORIA Publication_Information: Publication_Place: Cambridge, U.K. Publisher: Cambridge University Press Cross_Reference: Citation_Information: Originator: P.S. Chavez Jr. Publication_Date: 1986 Title: Processing Techniques for Digital Sonar Images from GLORIA Series_Information: Series_Name: Photogrammetric Engineering and Remote Sensing Issue_Identification: Vol. 52, No. 8, August 1986, p. 1133-1145 Publication_Information: Publication_Place: Falls Church, VA 22046 Publisher: American Society for Photogrammetry and Remote Sensing Cross_Reference: Citation_Information: Originator: P.S. Chavez Jr. Publication_Date: 1984 Title: U.S. Geological Survey mini image processing system (MIPS) Series_Information: Series_Name: Open-File Report Issue_Identification: 84-880 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: https://pubs.er.usgs.gov/publication/ofr84880 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: There are no attributes associated with a GeoTIFF image. Logical_Consistency_Report: not applicable Completeness_Report: All available imagery were used to create this mosaic. Data were acquired during four cruises using the 6.5 kHz GLORIA sidescan-sonar system and a 45-km total swath width. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Primary navigational control for this survey was by Loran-C supplemented by satellite navigation. Accuracy of location of the navigation fixes is estimated to be better than 100 meters. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: unknown Title: Not available from original metadata file Type_of_Source_Media: digital tape media Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 19860624 Ending_Date: 19890710 Source_Currentness_Reference: ground condition with the following date ranges: 19860624 to 19860703, 19880706 to 19880802, 19880805 to 19880831, 19890516 to 19890612 and 19890614 to 19890710 Source_Citation_Abbreviation: GLORIA pass data Source_Contribution: GLORIA data were logged to magnetic tape in 6-hour portions referred to as "passes". Each completed pass contained a maximum 720 "lines" of data at the usual 30-second pulse repetition rate. Each line consisted of a 1024 byte record that contained the port and starboard returns from a single ping as well as header information. These "passes" contained geometric and radiometric distortions which had to be corrected before they could be digitally mosaicked. Process_Step: Process_Description: The GLORIA "passes" necessary to complete the mosaic were retrieved from magnetic tape. Navigation data were merged into the individual "passes" to update the header information with depth and location coordinates. Source_Used_Citation_Abbreviation: GLORIA pass data Process_Date: Unknown Source_Produced_Citation_Abbreviation: "pass".mrg Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical address Address: 345 Middlefield Road MS 999 City: Menlo Park State_or_Province: CA Postal_Code: 94025 Country: USA Contact_Voice_Telephone: (650) 329-5078 Contact_Facsimile_Telephone: (650) 329-5190 Process_Step: Process_Description: Slant-Range correction, the first of two geometric corrections, were applied to the "passes". Slant-range error is mislocation of pixels in the cross-track direction compared to their proper location on a map. This error occurs due to the way that the sidescan-sonar senses distance to a target. After the slant-range correction has been made, the across-track location of targets is accurate. Source_Used_Citation_Abbreviation: "pass".mrg Process_Date: Unknown Source_Produced_Citation_Abbreviation: "pass".slr Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical address Address: 345 Middlefield Road MS 999 City: Menlo Park State_or_Province: CA Postal_Code: 94025 Country: USA Contact_Voice_Telephone: (650) 329-5078 Contact_Facsimile_Telephone: (650) 329-5190 Process_Step: Process_Description: A series of radiometric corrections were then applied to the "passes". The first enhancement was used to correct for shading problems that occur in the across-track direction and are a function of attenuation in range distance and transmitter power build-up. Source_Used_Citation_Abbreviation: "pass".slr Process_Date: Unknown Source_Produced_Citation_Abbreviation: "pass".shd Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical address Address: 345 Middlefield Road MS 999 City: Menlo Park State_or_Province: CA Postal_Code: 94025 Country: USA Contact_Voice_Telephone: (650) 329-5078 Contact_Facsimile_Telephone: (650) 329-5190 Process_Step: Process_Description: The next radiometric enhancement was applied in a two-part filtering process to remove the striped noise that can be found in side-scan sonar image in the across-track direction. The noise was removed by applying two separate boxcar filters: (1) a high-pass filter that will contain the high-frequency component of the image without the noise; and (2) a low-pass filter that will include the low-frequency component of the image without the noise. Source_Used_Citation_Abbreviation: "pass".shd Process_Date: Unknown Source_Produced_Citation_Abbreviation: "pass".hpf Source_Produced_Citation_Abbreviation: "pass".lpf Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical address Address: 345 Middlefield Road MS 999 City: Menlo Park State_or_Province: CA Postal_Code: 94025 Country: USA Contact_Voice_Telephone: (650) 329-5078 Contact_Facsimile_Telephone: (650) 329-5190 Process_Step: Process_Description: The two filtered images were combined to recreate an image similar to the original but without the noise. Source_Used_Citation_Abbreviation: "pass".lpf Source_Used_Citation_Abbreviation: "pass".hpf Process_Date: Unknown Source_Produced_Citation_Abbreviation: "pass".wco Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical address Address: 345 Middlefield Road MS 999 City: Menlo Park State_or_Province: CA Postal_Code: 94025 Country: USA Contact_Voice_Telephone: (650) 329-5078 Contact_Facsimile_Telephone: (650) 329-5190 Process_Step: Process_Description: The second geometric correction, aspect-ratio distortion, was applied to the "passes". The aspect-ratio distortion was removed by using the navigation data to compute the distance traveled by the ship. Given the distance traveled, the number of pixels (each representing 50 m) required along the particular segment was calculated. The original pixels were then duplicated the appropriate number of times to fill the space with 50-meter pixels and thus achieve a 1:1 ratio between along-track and across-track distances. The practice of duplication to create a square 50-meter pixel size was followed so that information in the across-track direction would not have to be omitted. Source_Used_Citation_Abbreviation: "pass".wco Process_Date: Unknown Source_Produced_Citation_Abbreviation: "pass".vel Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical address Address: 345 Middlefield Road MS 999 City: Menlo Park State_or_Province: CA Postal_Code: 94025 Country: USA Contact_Voice_Telephone: (650) 329-5078 Contact_Facsimile_Telephone: (650) 329-5190 Process_Step: Process_Description: A third radiometric enhancement, a 2 by 2 low-pass filter for smoothing the images, was applied to the "passes". Because the delta velocity correction typically stretches the imagery 1:2.5 times, a 2 by 2 low-pass filter is applied to the image to smooth and reduce the blockiness that results from the line duplication. The 2 by 2 low-pass filter smoothes out the blockiness introduced into the image without over smoothing and blurring the image. Source_Used_Citation_Abbreviation: "pass".vel Process_Date: Unknown Source_Produced_Citation_Abbreviation: "pass".2b2 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical address Address: 345 Middlefield Road MS 999 City: Menlo Park State_or_Province: CA Postal_Code: 94025 Country: USA Contact_Voice_Telephone: (650) 329-5078 Contact_Facsimile_Telephone: (650) 329-5190 Process_Step: Process_Description: A final radiometric enhancement was applied to the image to reduce the halo effect that occurs in the along-track direction near the nadir. This enhancement involved creating two separate images from the input image. The images were produced as a result of 151-line by 31- sample high-pass filter plus a 151-line by 401-sample low-pass filter. The two resultant images were then digitally combined to produce an image similar to the original but without the halo effect. Source_Used_Citation_Abbreviation: "pass".2b2 Process_Date: Unknown Source_Produced_Citation_Abbreviation: "pass".hal Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical address Address: 345 Middlefield Road MS 999 City: Menlo Park State_or_Province: CA Postal_Code: 94025 Country: USA Contact_Voice_Telephone: (650) 329-5055 Contact_Facsimile_Telephone: (650) 329-5190 Process_Step: Process_Description: After the geometric and radiometric corrections were applied, the data were ready for the digital mosaicking. The necessary segments of processed data, each representing about 6-hours of data acquisition, were spliced end-to-end to make continuous swaths for portions of the tracklines where the ship's heading remained generally constant and passed through the mosaic area. The segments were tone-matched by adjusting the average brightness to minimize the tonal contrast at the seams where they were joined. Latitude, longitude, and heading were determined along the trackline of each continuous segment of data at the start, end, and two intermediate points. These four control points, with eight additional points that were computed for the edges of the image segment, were used to position the segment within the map grid. Source_Used_Citation_Abbreviation: "pass".hal Process_Date: Unknown Source_Produced_Citation_Abbreviation: gak_q52_line"n" Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical address Address: 345 Middlefield Road MS 999 City: Menlo Park State_or_Province: CA Postal_Code: 94025 Country: USA Contact_Voice_Telephone: (650) 329-5078 Contact_Facsimile_Telephone: (650) 329-5190 Process_Step: Process_Description: When the individual trackline segments had been georeferenced, the next step was to digitally stencil the segments to remove unwanted data (i.e. noise). Interactively, a line was drawn on a video display outlining the portion of each image segment to be retained while comparing it to adjacent segments. Then all pixels outside the area enclosed by the line were converted to zero values, thereby retaining only that portion of the image desired. Finally, each stenciled segment was mosaicked to adjacent segments, sequentially building the composite map. In this way a digital file was created with the desired map projection for each imagery sheet (mosaic). Source_Used_Citation_Abbreviation: gak_q52_line"n" Process_Date: Unknown Source_Produced_Citation_Abbreviation: gak_q52 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical address Address: 345 Middlefield Road MS 999 City: Menlo Park State_or_Province: CA Postal_Code: 94025 Country: USA Contact_Voice_Telephone: (650) 329-5078 Contact_Facsimile_Telephone: (650) 329-5190 Process_Step: Process_Description: The binary image files of the GLORIA mosaics were imported into a PCI database file allowing the images to be georeferenced. The image georeference report was saved for future reference. Source_Used_Citation_Abbreviation: gak_q52.bin Process_Date: 20070822 Source_Produced_Citation_Abbreviation: gak_q52.pix; channel 1 Source_Produced_Citation_Abbreviation: gak_q52-georep.txt Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Valerie Paskevich Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: (508) 548-8700 Process_Step: Process_Description: The GLORIA image was exported from the PCI database file to a GeoTIFF image with an accompanying world file. Source_Used_Citation_Abbreviation: gak_q52.pix; channel 2 Process_Date: 20070822 Source_Produced_Citation_Abbreviation: gak_q52.tif Source_Produced_Citation_Abbreviation: gak_q52.tfw Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Valerie Paskevich Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: (508) 548-8700 Process_Step: Process_Description: The image was modified to flood-fill the background 0 (black) data value to 255 (white). After modification, the header portion of the image was updated to restore the georeferencing information. Source_Used_Citation_Abbreviation: gak_q52.tif Source_Used_Citation_Abbreviation: gak_q52.tfw Process_Date: 20070822 Source_Produced_Citation_Abbreviation: gak_q52.tif Source_Produced_Citation_Abbreviation: gak_q52.tfw Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Valerie Paskevich Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: (508) 548-8700 Process_Step: Process_Description: Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. Process_Date: 20170105 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Alan O. Allwardt Contact_Position: Contractor -- Information Specialist Contact_Address: Address_Type: mailing and physical address Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 831-460-7551 Contact_Facsimile_Telephone: 831-427-4748 Contact_Electronic_Mail_Address: aallwardt@usgs.gov Process_Step: Process_Description: Added keywords from Coastal and Marine Ecological Classification Standard (CMECS) to metadata. Process_Date: 20180426 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Alan O. Allwardt Contact_Position: Contractor -- Information Specialist Contact_Address: Address_Type: mailing and physical address Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 831-460-7551 Contact_Facsimile_Telephone: 831-427-4748 Contact_Electronic_Mail_Address: aallwardt@usgs.gov Process_Step: Process_Description: Edits to the metadata were made to fix any errors that MP v 2.9.46 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.). Added a landing page link as the first link in the identification section. Fixed the date format in the time period of content. Removed LIDAR bounding coordinates - an artifact of Esri and MP processing. Attempted to modify http to https where appropriate. Added a cross-reference online link. The source information was incomplete and had to be modified to meet the standard. 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. Process_Date: 20180503 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: VeeAnn A. Cross Contact_Position: Marine Geologist Contact_Address: Address_Type: Mailing and Physical Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: 508-548-8700 x2251 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: vatnipp@usgs.gov Process_Step: Process_Description: Crossref DOI link was added as the first link in the metadata. Process_Date: 20191118 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: VeeAnn A. Cross Contact_Position: Marine Geologist Contact_Address: Address_Type: Mailing and Physical Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: 508-548-8700 x2251 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: vatnipp@usgs.gov Process_Step: Process_Description: Added keywords section with USGS persistent identifier as theme keyword. Process_Date: 20200908 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: VeeAnn A. Cross Contact_Position: Marine Geologist Contact_Address: Address_Type: Mailing and Physical Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: 508-548-8700 x2251 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: vatnipp@usgs.gov Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Pixel Row_Count: 4666 Column_Count: 3820 Vertical_Count: 1 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Map_Projection: Map_Projection_Name: Lambert Conformal Conic Lambert_Conformal_Conic: Standard_Parallel: 50.000000 Standard_Parallel: 59.000000 Longitude_of_Central_Meridian: -144.000000 Latitude_of_Projection_Origin: 0.000000 False_Easting: 0.000000 False_Northing: 0.000000 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: row and column Coordinate_Representation: Abscissa_Resolution: 50.000000 Ordinate_Resolution: 50.000000 Planar_Distance_Units: meters Geodetic_Model: Horizontal_Datum_Name: D_WGS_1984 Ellipsoid_Name: WGS_1984 Semi-major_Axis: 6378137.000000 Denominator_of_Flattening_Ratio: 298.257224 Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Overview: There are no attributes associated with a GeoTIFF image. Image pixel values contain acoustic reflectivity values normalized to an 8-bit data range (0-255). Low-backscatter is represented by dark tones (low values), and high-backscatter is represented by bright tones (high values). Entity_and_Attribute_Detail_Citation: U.S. Geological Survey Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical address Address: 345 Middlefield Road MS 999 City: Menlo Park State_or_Province: CA Postal_Code: 94025 Country: USA Contact_Voice_Telephone: (650) 329-5078 Contact_Facsimile_Telephone: (650) 329-5190 Resource_Description: Downloadable Data Distribution_Liability: Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: TIFF Format_Version_Number: Not available from original metadata Format_Specification: GeoTIFF Format_Information_Content: A zip archive containing the GeoTIFF image, world file, browse graphics and metadata files. File_Decompression_Technique: zip archive Transfer_Size: 8.23 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://pubs.usgs.gov/of/2010/1332/gloria_data/gulf_of_alaska/gak_q52.zip Access_Instructions: Data are available for download on the World Wide Web (WWW). Offline_Option: Offline_Media: DVD-ROM Recording_Capacity: Recording_Density: 4.75 Recording_Density_Units: Gbytes Recording_Format: UDF Fees: None Technical_Prerequisites: The sidescan-sonar mosaic is available as a GeoTIFF image with accompanying world file and georeference report. To utilize this data, the user must have an image viewer, image processing or GIS software package capable of importing a GeoTIFF image. If the georeferencing information cannot be imported, the user may wish to obtain the georeference information contained in a separate file included in the zip file. Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: (650) 329-5078 Contact_Facsimile_Telephone: (650) 329-5190 Resource_Description: Downloadable Data Distribution_Liability: Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: TIFF Format_Version_Number: Not available from original metadata Format_Specification: GeoTIFF Format_Information_Content: A zip archive containing the GeoTIFF image, world file, browse graphics and metadata files. File_Decompression_Technique: zip archive Transfer_Size: 8.23 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://pubs.usgs.gov/of/2010/1332/gloria_data/gulf_of_alaska/gak_q52.zip Access_Instructions: Data are available for download on the World Wide Web (WWW). Offline_Option: Offline_Media: DVD-ROM Recording_Capacity: Recording_Density: 4.75 Recording_Density_Units: Gbytes Recording_Format: UDF Fees: None Technical_Prerequisites: The sidescan-sonar mosaic is available as a GeoTIFF image with accompanying world file and georeference report. To utilize this data, the user must have an image viewer, image processing or GIS software package capable of importing a GeoTIFF image. If the georeferencing information cannot be imported, the user may wish to obtain the georeference information contained in a separate file included in the zip file. Metadata_Reference_Information: Metadata_Date: 20211111 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Valerie Paskevich Contact_Position: Information Specialist / GIS Coordinator, retired Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: (508) 548-8700 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: whsc_data_contact@usgs.gov Contact_Instructions: The metadata contact email address is a generic address in the event the metadata contact is no longer with the USGS Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: local time Metadata_Access_Constraints: None Metadata_Use_Constraints: None