Attribute_Accuracy_Report:
Attributes relay information about the object ID (FID), Esri Object ID (polyline), length of tracklines (m), line number, type of sonar system used to acquire data, the frequency of the sonar system, swath width of the sonar system, USGS unique cruise identification, the date of acquisition and the Julian Day. Attributes were checked for consistency and for accuracy of descriptive information.
All sidescan-sonar data were collected during USGS cruise 2005-004-FA using a Klein system 3000 sidescan-sonar system. Quality control was conducted during processing of the data. Any spurious data or artifacts were removed or minimized.
This shapefile contains lines 43 - 112 of sidescan-sonar data collected on JD 207(07/26/2005) during USGS field activity 2005-004-FA. Lines 43 - 112 were a 'rerun' of lines 1 - 42 to try to improve on the data quality as there were significant system errors and malfunctions during data collection on JD 206 (07/25/2005). Lines 1 - 42 are not included in this dataset. They were not used for interpretative purposes. Lines 43 - 112 were used to generate the sidescan-sonar mosaic.
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
Navigation was acquired with Wide Area Augmentation System ( WAAS), which is accurate to + or - 1 to 2 meters, horizontally. Navigation data were acquired with a LGBX Pro receiver and sent directly to the sidescan-sonar acquisition software, L3-Klein Associates, SonarPro. The LGBX Pro received WAAS positions from an antenna located on the port, aft roof of the cabin. The sidescan-sonar towfish was towed at a shallow depth, close to the lake surface due to the shallow waters of the survey area. Layback was measured upon deployment of the towfish. The following offsets are measured prior to deployment of the sidescan-sonar towfish and entered into SonarPro: height of the block, offset from DGPS (WAAS) antenna to the block, and height of the DGPS antenna above the waterline. Considering errors in measuring towfish layback, as well as accuracy of WAAS, horizontal accuracy of the sidescan-sonar data are conservatively assumed to be + or - 10 meters.
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: Unpublished Material
Title: Raw sidescan-sonar data
Type_of_Source_Media: disc
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 20070726
Source_Currentness_Reference: ground condition of field activity
Source_Citation_Abbreviation: none
Source_Contribution:
Data were acquired with an L3-Klein Associates 3000 digital, dual-frequency, sidescan-sonar (www.l-3klein.com). Dual frequencies are nominally 100 (132 kHz) and 500 (445 kHz) kHz. The sidescan-sonar was towed aft the R/V Rafael. Line spacing was 50-meters throughout the survey area. Data files were recorded with SonarPro (2005) in XTF (extended-Triton Format) format at a 0.03-sec ping rate yielding a 50-meter range (100-meter swath). The 100 kHz data were used to generate the sidescan-sonar mosaic. The data range within the sidescan-sonar mosaic (digital number values (DN) of the 8-bit image) is 0 - 254, with the background value (i.e. No DATA) set to 255.
Process_Step:
Process_Description:
XSonar/ShowImage sidescan-sonar processing software was used to process the raw XTF sonar data following the methodology of Danforth, (1997). A 4 across track x 3 along track pixel median filter was applied to the raw sidescan-sonar data to remove speckle noise and a normalization of 4095 was applied to adjust the dynamic range within the output processed file. Processed data are stored as 8-bit. Navigation were also extracted from the raw data at 30-second intervals and saved in an ASCII file. Quality checks were conducted on the navigation to eliminate spurious or duplicate navigation fixes. The sonar data were further processed to correct for towfish altitude (i.e. proper tracking of the lakefloor), and slant-range and beam pattern distortions inherent in the sonar data. Processed sonar files were then merged with the edited navigation. Processed sonar files were then mapped at a 1-meter resolution in UTM coordinates (UTM, Zone 19N, WGS84, meters) and saved in two XSonar/ShowImage mosaic files representing odd and even (i.e. every other line) sonar tracklines, or files.
Below are the typical parameters for processing with XSonar: File Type: XTF, Low Frequency (132 kHz)
Setup Option: Navigation= Lat/Lon, Navigation Interval= 2 minute
Demultiplexing Range and Filter options: Across track=4 (pixels), Along track= 3 (pixels), Port/Starboard Normalize = 4095 (default), Port High Pass: 65535 (default), Input= 16 bit, Normalize Image= yes.
Beam Pattern Correction options: Number of lines= 100 Ping, overlap=50, Max beam angle= 90 (default), Response angle=55 (default,) Data normalization (0-255)=1 (default), Port/Stbd Tone Adjustment= "on" and "Normal"
Jane F. Denny performed this and all subsequent process steps.
Process_Date: 2005
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Jane F. Denny
Contact_Organization: U.S. Geological Survey
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Road
City: Woods Hole
State_or_Province: Massachusetts
Postal_Code: 02543
Country: USA
Contact_Voice_Telephone: 508-548-8700 x2311
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: jdenny@usgs.gov
Process_Step:
Process_Description:
A c-shell script was used to reformat the output from degrees decimal minutes to decimal degrees. Proj and AWK were used to convert decimal degrees to eastings and northings (based on UTM Zone 19 N, meters, WGS 84) and to reformat the output as a comma delimited ASCII file including headers listing field names (Easting, Northing, Line Number, Julian Day, Hour, Minute, Second, Longitude, Latitude).
Process_Date: 2005
Process_Step:
Process_Description:
The ASCII file (*.csv) was imported into Esri ArcMap 9.0 using Tools - Add XY Data and converted to an event theme. The event theme was then saved to a point shapefile and the projection was defined as Geographic Coordinate System, WGS84 (GCS_WGS_1984). The point shapefile was visually inspected for spurious data points.
Process_Date: 2005
Process_Step:
Process_Description:
The point shapefile containing 30-second navigation was used as input for a tool in VACExtras (version 1.8), a VB collection of tools developed by VeeAnn Cross (USGS-WHCMSC), that converts point data to a new polyline (vector) shapefile, based on the order of records contained within one attribute field. The line number field was used to define the point order and as the unique line identifier.
Process_Date: 2005
Process_Step:
Process_Description:
The length of each line segment was calculated and included in a new attribute field using XTools Pro for ArcGIS desktop (version 6.2.0), specifying UTM Zone 19 N, WGS 84 - meters. Year, System, Swath, Cruise_ID,Frequency and Julian Day (JD) fields were added to the attribute table within ArcMap 9.0.
The vector shapefile was then reprojected to the Geographic Coordinate System, WGS84 using Arc Toolbox, Data Management Tools, Projections and Transformations, Feature, Project.
Arc Toolbox, Data Management Tools, Projections and Transformations, Project was then used to project the shapefile from UTM, Zone 19 N, meters, WGS84 to Geographic Coordinate system, WGS84.
Process_Date: 2005
Process_Step:
Process_Description:
ArcGIS 9.3, Xtools 7.1.0 (Build 738) was used to convert polyines to points using Xtools, Feature Conversion, Convert Features to Points, generating a new shapefile. Xtools was then used to add X,Y coordinates to the new shapefile table, using Xtools, Table Operations, Add X,Y,Z coordinates. The table was then exported to a text file using, Xtools, Table Operations, Export table to txt. The txt file was saved as a *.csv. The *csv can then be used outside of the ArcGIS 9.3 environment to generate trackline data, if neeed.
Process_Date: 2014
Process_Step:
Process_Description:
The online links to the data were updated to reflect the new server hosting the data. Additionally, other small edits could be made to the metadata, such as modifying http to https where appropriate. The metadata date (but not the metadata creator) was edited to reflect the date of these changes.
Process_Date: 20170406
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: USGS Thesaurus keywords added to the keyword section.
Process_Date: 20180720
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
