Identification_Information: Citation: Citation_Information: Originator: David S. Foster Originator: VeeAnn A. Cross Publication_Date: 2005 Title: TIFF Sidescan-Sonar mosaic of Lake Mohave : Geographic NAD83 Coordinates Geospatial_Data_Presentation_Form: remote-sensing image Online_Linkage: http://pubs.usgs.gov/of/2004/1247/data/sidescan/geographic/sscan_geog.tif.zip Larger_Work_Citation: Citation_Information: Originator: VeeAnn A. Cross Originator: David S. Foster Originator: David C. Twichell Publication_Date: 2005 Title: Lake Mohave Geophysical Survey 2002: GIS Data Release Series_Information: Series_Name: Open-File Report Issue_Identification: 2004-1247 Publication_Information: Publication_Place: Woods Hole Science Center, Woods Hole, MA Publisher: U.S. Geological Survey Online_Linkage: http://pubs.usgs.gov/of/2004/1247 Description: Abstract: Lake Mohave is one of several multi-purpose reservoirs that have been constructed on the Colorado River. The lake was formed upon completion of the Davis Dam in 1953. No mapping of the floor of the lake had been conducted since completion of the Davis Dam. The U.S. Geological Survey, in cooperation with researchers from the University of Nevada Las Vegas, completed a geophysical survey of this lake in April 2002. The survey included collection of sidescan sonar imagery of nearly the entire lake floor, and high-resolution seismic-reflection profiles along widely spaced lines throughout the lake. The detailed mapping of the lake floor was used to determine the amount of sediment that had accumulated in the lake since impoundment, its distribution, and the processes of deposition. Purpose: This sidescan-sonar imagery is used to map the morphology of the lake floor and determine the extent of sediment distribution on the lake floor. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20020418 Ending_Date: 20020425 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -114.733562 East_Bounding_Coordinate: -114.549422 North_Bounding_Coordinate: 35.870509 South_Bounding_Coordinate: 35.199193 Keywords: Theme: Theme_Keyword_Thesaurus: General Theme_Keyword: CMGP Theme_Keyword: Coastal and Marine Geology Program Theme_Keyword: images Theme_Keyword: lake Theme_Keyword: OF 2004-1247 Theme_Keyword: Open-File Report Theme_Keyword: reservoir Theme_Keyword: sidescan Theme_Keyword: sidescan sonar Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Theme_Keyword: Woods Hole Science Center Theme_Keyword: DF1000 Theme_Keyword: TIFF Theme_Keyword: field activity identifier H-1-02-SW Theme_Keyword: field activity serial number 02020 Place: Place_Keyword_Thesaurus: General Place_Keyword: Arizona Place_Keyword: Colorado River Place_Keyword: Hoover Dam Place_Keyword: Lake Mohave Place_Keyword: Las Vegas Place_Keyword: Mojave Desert Place_Keyword: Nelson's Landing Place_Keyword: Nevada Place_Keyword: North America Place_Keyword: United States Access_Constraints: None. Use_Constraints: The U.S. Geological Survey must be referenced as the originator of the dataset in any future products or research derived from these data. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: David S. Foster Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Rd. City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: (508) 548-8700 x2271 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: dfoster@usgs.gov Native_Data_Set_Environment: Microsoft Windows 2000 Version 5.0 (Build 2195) Service Pack 4; ESRI ArcCatalog 8.3.0.800 Cross_Reference: Citation_Information: Originator: W.W. Danforth Originator: T.F. O'Brien Originator: W.C. Schwab Publication_Date: 1991 Title: USGS image processing system: near real-time mosaicking of high-resolution sidescan-sonar data Series_Information: Issue_Identification: Jan. 1991 Publication_Information: Publisher: Sea Technology Cross_Reference: Citation_Information: Originator: V.F. Paskevich Publication_Date: 1992 Title: Digital mapping of sidescan sonar data with the Woods Hole Image Processing System software Series_Information: Series_Name: Open-File Report Issue_Identification: 92-536 Publication_Information: Publisher: U.S. Geological Survey Cross_Reference: Citation_Information: Originator: V.F. Paskevich Publication_Date: 1996 Title: MAPIT: An improved method for mapping digital sidescan sonar data using the Woods Hole Image Processing System (WHIPS) Software Series_Information: Series_Name: Open-File Report Issue_Identification: 96-281 Publication_Information: Publisher: U.S. Geological Survey Data_Quality_Information: Positional_Accuracy: Horizontal_Positional_Accuracy: Quantitative_Horizontal_Positional_Accuracy_Assessment: Horizontal_Positional_Accuracy_Value: 10-30m Horizontal_Positional_Accuracy_Explanation: The ship was navigated with a PLGR system with an assumed navigational accuracy of +/- 10m. Range to towfish was used to estimate the towfish position. Due to the inherent inaccuracies in this method, plus navigational smoothing and mosaicking issues, the accuracy is assumed to be closer to the 20-30m value. Lineage: Process_Step: Process_Description: Sidescan sonar imagery was collected using an Edgetech DF1000 sidescan sonar system and logged to a Triton QMIPS data logging computer. The data were collected at a 150m, 200m, 400m, or 600m swath, 1024 pixels/side, 16-bit. The digital sidescan data were then processed and mapped to provide proper geographic locations of features identified in the imagery. The processing steps included subsampling the raw sidescan data using a median filtering routine to suppress speckle noise and reduce file size, and correct for slant-range distortion, signal attenuation, and dropped sonar lines using XSonar (Danforth et al., 1991). Process_Step: Process_Description: The digital sidescan data were then processed and mapped to provide proper geographic locations of features identified in the imagery. The processing steps included subsampling the raw sidescan data using a median filtering routine to suppress speckle noise and reduce file size, and correct for slant-range distortion, signal attenuation, and dropped sonar lines using XSonar (Danforth et al., 1991). Process_Step: Process_Description: The imagery was mapped into its proper geographic location using the XSonar software. Individual sidescan swaths were mapped with each pixel geographically positioned at a resolution of 2 m/pixel. Process_Step: Process_Description: Non-overlapping swaths were then brought into the remote sensing software package PCI. The techniques for generating the composite digital sidescan mosaic are summarized by Paskevich (1996). The imagery portion was then cut out and written to a PCI channel with a white background. A LUT was applied to the imagery such that the image contains values 0-254. Because the background is 255, that color can be made transparent when viewing in a GIS. Process_Step: Process_Description: The image was then exported from PCI as a geotiff image with an associated world file. Process_Step: Process_Description: Because the original mosaicking was done in UTM, Zone 11, WGS84, the resulting TIFF image was then reprojected to the geographic, NAD83 datum using BlueMarble Geographic Transformer, version 5.0. An affine transformation, with a central latitude of 35.534855555556 was used in this process. Process_Step: Process_Description: This TIFF image was then opened in Corel PhotoPaint v. 10 and saved with PackBit compression. Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Pixel Row_Count: 37241 Column_Count: 8312 Vertical_Count: 1 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Geographic_Coordinate_Units: Decimal degrees Planar: Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: row and column Coordinate_Representation: Abscissa_Resolution: 0.000022 Ordinate_Resolution: 0.000018 Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1983 Ellipsoid_Name: Geodetic Reference System 80 Semi-major_Axis: 6378137.000000 Denominator_of_Flattening_Ratio: 298.257222 Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Overview: The pixel value represents the DN return value of the sidescan-sonar system. A high value (i.e. 255) indicates a highly reflective lake floor surface, while a low value (i.e. 0) indicates low reflectance. Distribution_Information: Distributor: Contact_Information: Contact_Person_Primary: Contact_Person: David S. Foster Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Rd. City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: (508) 548-8700 x2271 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: dfoster@usgs.gov Resource_Description: Downloadable Data Distribution_Liability: These data were prepared by an agency of the United States Government. Neither the United States government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof. Although all data published in this publication have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and/or the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data, software, or related materials. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Transfer_Size: 22.837 Metadata_Reference_Information: Metadata_Date: 20040928 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: VeeAnn A. Cross Contact_Organization: U.S. Geological Survey Contact_Position: Marine Geologist Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Rd. 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 Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: local time Metadata_Extensions: Online_Linkage: http://www.esri.com/metadata/esriprof80.html Profile_Name: ESRI Metadata Profile