Identification_Information: Citation: Citation_Information: Originator: United States Geological Survey (USGS), Coastal and Marine Geology (CMG), Chief Scientist (James V. Gardner) Publication_Date: 2002 Title: Multibeam Backscatter of the Long Beach Shelf, California Geospatial_Data_Presentation_Form: XYZ ASCII Description: Abstract: XYZ ASCII format data generated from the 1999 multibeam sonar survey of the Long Beach Shelf, California. The data include high-resolution acoustic, calibrated backscatter. Purpose: These data are intended for science researchers, students, policy makers, and the general public. The data can be used with geographic information systems (GIS) or other software to display bathymetry and backscatter data of the Long Beach Shelf, California. Supplemental_Information: Information for USGS Coastal and Marine Geology related activities are online at < http://walrus.wr.usgs.gov/infobank/c/c199sc/html/c-1-99-sc.meta.html > Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 19990414 Ending_Date: 19990518 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: As needed Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -118.357 East_Bounding_Coordinate: -117.816 North_Bounding_Coordinate: 33.732 South_Bounding_Coordinate: 33.541 Keywords: Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: Marine Geology Theme_Keyword: Multibeam Theme_Keyword: Backscatter Theme_Keyword: Water Depth Theme_Keyword: Ocean Floor Topography Place: Place_Keyword_Thesaurus: None Place_Keyword: Long Beach Shelf Place_Keyword: CA Place_Keyword: Southern California Place_Keyword: USA Access_Constraints:None Use_Constraints: Please recognize the U.S. Geological Survey (USGS) as the source of this information. USGS-authored or produced data and information are in the public domain. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: James V. Gardner Contact_Organization: United States Geological Survey (USGS) Coastal and Marine Geology (CMG) Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical address Address: USGS, MailStop 999, 345 Middlefield Road City: Menlo Park State_or_Province: CA Postal_Code: 94025-3561 Country: USA Contact_Voice_Telephone: (650) 329-5469 Contact_Facsimile_Telephone: (650) 329-5411 Contact_Electronic_Mail_Address: jvgardner@usgs.gov Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Not determined. Logical_Consistency_Report: Point features present. Completeness_Report: Complete Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: 0.5 meters Vertical_Positional_Accuracy Vertical_Positional_Accuracy_Report: 0.05 percent of the water depth. Depths corrected to mean lower low water datum Lineage: Process_Step: Process_Description: The multibeam bathymetry and acoustic backscatter data were collected along a continuous swath perpendicular to the direction of the ship using a Kongsberg Simrad dual EM3000 multibeam sonar system. The data are cleaned of bad navigation and depth readings and corrected for tides to mean lower low water datum. The acoustic backscatter readings are gridded into a common grid. The gridded data are converted to ArcInfo GRID format using ArcInfo's ASCIIGRID command. The GRID was converted to an XYZ ASCII file by using the GRIDPOINT, ADDXY, and Tables UNLOAD commands. Process_Date: 19990518 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: James V. Gardner Contact_Organization: United States Geological Survey (USGS) Coastal and Marine Geology (CMG) Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical address Address: USGS, MailStop 999, 345 Middlefield Road City: Menlo Park State_or_Province: CA Postal_Code: 94025-3561 Country: USA Contact_Voice_Telephone: (650) 329-5469 Contact_Facsimile_Telephone: (650) 329-5411 Contact_Electronic_Mail_Address: jvgardner@usgs.gov Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Point Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Point Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 0.00016 Longitude_Resolution: 0.00016 Geographic_Coordinate_Units: Decimal degrees Geodetic_Model: Horizontal_Datum_Name: WGS84 Ellipsoid_Name: WGS84 Semi-major_Axis: 6378137.00 meters Denominator_of_Flattening_Ratio: 0.003352811 Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Overview: Sample of Backscatter XYZ ASCII file > Longitude, Latitude, DN Value > (decimal degree, decimal degree, DN value) >-117.97421,33.63640,207.696 >-117.97413,33.63640,206.398 >-117.97405,33.63640,203.770 >-117.97398,33.63640,201.170 >-117.97390,33.63640,201.098 >-117.97382,33.63640,202.064 >-117.97374,33.63640,202.693 >-117.97367,33.63640,202.720 >-117.97444,33.63640,201.992 Entity_and_Attribute_Detail_Citation: none Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: United States Geological Survey (USGS) Information Services Contact_Address: Address_Type: mailing and physical address Address: 345 Middlefield Rd., MS-999 City: Menlo Park State_or_Province: CA Postal_Code: 94025 Country: USA Contact_Voice_Telephone: (650)329-5469 Resource_Description: C-1-99-SC data set Distribution_Liability: These data not intended for navigational purposes. Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, these data and information are provided with the understanding that they are not guaranteed to be usable, timely, accurate, or complete. Users are cautioned to consider carefully the provisional nature of these data and information before using them for decisions that concern personal or public safety or the conduct of business that involves substantial monetary or operational consequences. Conclusions drawn from, or actions undertaken on the basis of, such data and information are the sole responsibility of the user. Neither the U.S. Government nor any agency thereof, 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 data, software, information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. Trade, firm, or product names and other references to non-USGS products and services are provided for information only and do not constitute endorsement or warranty, express or implied, by the USGS, USDOI, or U.S. Government, as to their suitability, content, usefulness, functioning, completeness, or accuracy. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: ASCII Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: none Fees: None Metadata_Reference_Information: Metadata_Date: 20020206 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Pete Dartnell Contact_Organization: United States Geological Survey (USGS) Coastal and Marine Geology (CMG) Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical address Address: USGS, MailStop 999, 345 Middlefield Road City: Menlo Park State_or_Province: CA Postal_Code: 94025-3561 Country: USA Contact_Voice_Telephone: (650) 329-5460 Contact_Facsimile_Telephone: (650) 329-5411 Contact_Electronic_Mail_Address: pdartnell@usgs.gov Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata ("CSDGM version 2") Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: universal time