This grid does not include all bathymetric data collected in the northern Cape Cod Bay survey area. Data collected along transit lines, east-west seismic-reflection tie lines and other sections of lines of poor quality were excluded from this grid. The "Mosaic" attribute in the CCB_BathTracklines shapefile published in this report identifies the 524 lines that were included and the 60 lines that were not included in this grid.
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
Field activity 06012: The SWATHplus transducers were mounted on a rigid pole, approximately 2.6 m below the water line, along the starboard side of the R/V Megan T. Miller. Position data were provided by an Ashtech Z-Surveyor Extreme for real-time kinematic (RTK) navigation (an Ashtech BR2G Differential Global Positioning System (DGPS) was used as a backup navigation system) and recorded to the raw data files (SXR) via Swath Processor (version 2.07) acquisition software. During some portions of the survey, technical difficulties caused the GPS systems to malfunction and lose the "fixed" RTK signal. When this occurred, the navigation system defaulted to a "float" RTK, and then to a GPS (stand alone) signal, after which the navigation signal was lost completely. Surveying was halted until a reliable GPS signal was restored. A conservative estimate of positional accuracy is +/- 2 meters, but when the navigation system was providing the "fixed" RTK signal, positional accuracy is <1 m.
Field activities 07001, 07002, and 08002: The SWATHplus transducers were mounted on a rigid pole from the bow of the R/V Rafael, approximately 0.5 m below the water line during surveys 07001 and 08001, and 2.6 m below the water line on the starboard side for survey 07002. Position data were recorded by Hypack software to Hypack raw files using an Ashtech Z-Surveyor Extreme for real-time kinematic (RTK) navigation, and an Ashtech BR2G for Differential Global Positioning System (DGPS) navigation. DGPS navigation from the primary F180 antenna was recorded to the raw sonar data files (SXR) via SWATHplus acquisition software. A conservative estimate of positional accuracy is +/- 2 meters.
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report:
Based on SWATHplus interferometric sonar system specifications, vertical accuracy of the raw data may approximate 1% of water depth, which translates to 0.1 0.6 meters within the northern Cape Cod Bay survey area. RTK-GPS was used to establish water-level heights relative to Mean Lower Low Water (MLLW), providing decimeter-scale accuracies. Tide-correction was done in post-processing (see process steps). Refraction artifacts were minimized by acquiring a range of sound velocity profiles throughout the survey area to model the sound velocity structure of the water column. Changes in vessel draft due to fuel and water usage were not considered.
Source_Information:
Source_Citation:
Citation_Information:
Originator:
Information unavailable from original metadata. Assumed to be USGS.
Publication_Date: unknown
Title: Information unavailable from original metadata.
Other_Citation_Details:
This file had a source contribution, but no other source information. This information had to be modified to meet the standard.
Type_of_Source_Media: Information unavailable from original metadata.
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20060816
Ending_Date: 20080507
Source_Currentness_Reference:
Information unavailable from original metadata, but assumed to be the same as the time period of content. Ground condition of four separate date ranges - 20060816 to 20060823; 20070429 to 20070503; 20070725 to 20070807; 20080429 to 20080507.
Source_Citation_Abbreviation: Information unavailable from original metadata.
Source_Contribution:
Sonar Configuration: Bathymetry data were acquired using a Systems Engineering and Assessment Ltd. (SEA) SWATHplus interferometric sonar operating at 234 kHz (06012, 07001, 08002) or 117 kHz (07002). Survey lines were run at an average speed of 5 knots and were spaced 75-200 m apart to obtain overlapping swaths of data and full coverage of the seafloor. During USGS field activities 06012 and 07002, the SWATHplus transducers were mounted on a rigid pole on the starboard side of the R/V Megan Miller, about 2.6 m below the waterline.
During 06012, a TSS DMS 2-05 motion reference unit was mounted directly above the sonar transducers and continuously recorded and sent vertical displacement (heave) and attitude (pitch and roll) of the vessel during acquisition to the SWATHplus software. During 06012 vessel heading was determined by a KVH compass that was corrected for magnetic variation of +15.583 degrees (from NOAA Chart number13246 36th ed., Mar. 10/01) during post processing. During 07002, a Coda Octopus F180 inertial-motion unit, mounted directly above the transducers, measured true heading, vertical displacement (heave) and attitude (pitch and roll) of the vessel during acquisition.
Field activities 07001 and 08002: the SWATHplus transducers were mounted on a rigid pole on the bow of the R/V Rafael, about 0.5 m below the waterline. A Coda Octopus F180 inertial-motion unit, mounted directly above the transducers, measured true heading, vertical displacement (heave) and attitude (pitch and roll) of the vessel during acquisition.
Navigation:
Field activity 06012: Real-Time Kinematic (RTK) GPS navigation was used to determine the horizontal and vertical position (xyz) of the GPS antenna mounted directly above the SWATHplus transducers with sub-meter accuracy. The RTK-corrected coordinates were transmitted to the ship from a land-based RTK-GPS station established by the USGS at NOAA Tidal Station #8446009 in Brant Rock Harbor, MA.
Field activities 07001, 07002, and 08002: Differential GPS (DGPS) navigation was used to determine the horizontal position (x,y) of the GPS antenna mounted directly above and forward (F180R primary antenna, 0.5 meters) of the SWATHplus transducers with +/- 1-2 meter accuracy. RTK-GPS was used to determine the vertical position of the Ashtech GPS antenna (z) with sub-meter accuracy.
Vertical coordinates for all four surveys were referenced to Mean Lower Low Water (MLLW) using the offset between the North American Vertical Datum of 1988 (NAVD 88) and MLLW published for the tidal benchmark. Horizontal (x and y) and vertical (z) offsets between the transducers, motion sensor, and GPS antenna were precisely measured and recorded within the SWATHplus acquisition software (SEA Swath Processor (2005)), which established the motion sensor as the common reference point during data acquisition.
Speed of Sound:
Sound-velocity profiles were collected approximately every 2 hours by a hand-casted Applied MicroSystems SV Plus sound velocimeter. The depth of the transducers below the sea surface was measured and recorded within the SWATHplus acquisition software, and used as a reference point for deriving the acoustic ray path based on sound velocity profiles.
Tides: During post-processing, soundings were referenced to local MLLW by using orthometric to chart datum offsets obtained from NOAA Tidal Station #8446009 at Brant Rock Harbor, Massachusetts. Data were processed and gridded by using the SEA SWATHplus Swath Processor (version 10.0) CARIS Hydrographic Information Processing System (HIPS version 6.1).
Process_Step:
Process_Description:
Step 1:
Process GPS Tides Data all four surveys:
Depths were corrected to Mean Lower Low Water (MLLW) using 1 second RTK-GPS heights of the GPS receiver mounted over the SWATHplus sonar head. These heights were extracted from each HYPACK navigation file using the AWK script "doRTK1_by_line_FIX" and smoothed in MATLAB (version 7.20.232 R2006a) using a third order polynomial. The smoothed 1 second heights were averaged to 1 minute heights and formatted for input to Swath Processor using the AWK script "DoRTK2". The resulting ASCII text file was then formatted to the Swath Processor format of HH:MM DD/MM/YYYY TTTTT.TTT and imported to tide table in the SEA Swath Processor session file (sxs). During the next step the tide data is merged into the bathymetric soundings data during the conversion of SWATHplus raw (sxr) files to SWATHplus processed (sxp) files. Processing occurred in 2006, 2007, and 2008.
Process_Date: 2008
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Brian Andrews
Contact_Organization: U.S. Geological Survey
Contact_Position: Geographer
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd.
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Country: USA
Contact_Voice_Telephone: 508-548-8700 x2348
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: bandrews@usgs.gov
Process_Step:
Process_Description:
Step 2: Raw to Processed Conversion all four surveys:
Each raw SWATHplus bathymetric sonar file (sxr) was converted to a SWATHplus processed file (sxp) using SEA SWATHplus Swath Processor (ver. 3.5 in 2006, 2007 and version 3.6 in 2008). During the conversion process, sound velocity profiles were used to minimize potential refraction artifacts from fluctuations in the speed of sound within the water column. Various bathymetric filters were applied to eliminate sounding outliers. During this conversion process the tidal information from the previous process step was merged into the new processed file (sxp). The filters in Swath Processor reduced the appearance of an artifact observed in the port side of the bathymetric data from survey 06012; probably the result of a multi-pathing sound wave off the hull of the survey vessel. Although minimized, this striped artifact may still be visible in the final bathymetry grid, especially in areas of little local relief. Processing occurred in 2006, 2007, and 2008.
Process_Date: 2008
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Brian Andrews
Contact_Organization: U.S. Geological Survey
Contact_Position: Geographer
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Country: USA
Contact_Voice_Telephone: 508-548-8700 x2348
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: bandrews@usgs.gov
Process_Step:
Process_Description:
Step 3: SwathPlus to CARIS Conversion: A new CARIS HIPS project (ver. 6.1) was created for each of the four surveys with projection information set to Universal Transverse Mercator (UTM) Zone 19, WGS84. Each SWATHplus processed file (sxp) was imported to the new CARIS project using the Import/Conversion Wizard. A 5 meter resolution Bathymetric and Statistical Error (BASE) Surface was created from the files for each Julian day. The BASE surface for each day was reviewed for any inconsistencies or data anomalies. Navigation was edited as needed using the navigation editor tool in CARIS. Filters were applied to each line including beam to beam slopes and across track angle. The CARIS refraction editor was used to adjust the speed of sound in some cases to flatten out the depth profiles produced by localized variations in speed of sound through the water column. Small refraction artifacts remain in the flat areas of the southeast corner of the survey area from survey 07002. Processing occurred in 2006, 2007, and 2008.
Process_Date: 2008
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Brian Andrews
Contact_Organization: U.S. Geological Survey
Contact_Position: Geographer
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Country: USA
Contact_Voice_Telephone: 508-548-8700 x2348
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: bandrews@usgs.gov
Process_Step:
Process_Description:
Step 4:Combine HDCS files for all four surveys:
Make a new CARIS HIPS project that contains only those processed line files from all four surveys that will be used for the final bathymetric grid. A 5 meter BASE surface was created (CCB_BathAll_5m) covering the spatial extent of all four surveys within northern Cape Cod Bay.
Process_Date: 200911
Source_Produced_Citation_Abbreviation: CCB_BathAll_5m.hns
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Brian Andrews
Contact_Organization: U.S. Geological Survey
Contact_Position: Geographer
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Country: USA
Contact_Voice_Telephone: 508-548-8700 x2348
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: bandrews@usgs.gov
Process_Step:
Process_Description:
Step 5: CARIS to ArcInfo Conversion:
The 5 meter resolution CARIS BASE (CCB_BathAll5m.hns) surface was imported to Interactive Visualization Systems (IVS) 3D Data Magician (DMagic ver 6.1) using the "import gridded data" function and converted to a interim IVS Digital Terrain Model (DTM) and geo file (CCB_Bath5m,dtm, .geo). The DTM file was then exported to an ASCII Raster using the function "export gridded data" using the ArcInfo no data format of -9999. The ASCII raster file (ccb_all5m.asc) was then imported to ArcGIS (ver. 9.3) as a 32-bit floating point ArcRaster grid.(ccb_bath_5m). The projection information was defined as UTM Zone 19, WGS_84 for the final grid using ArcToolbox "Define Projection" tool (ver. 9.3).
Process_Date: 200912
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Brian Andrews
Contact_Organization: U.S. Geological Survey
Contact_Position: Geographer
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Country: USA
Contact_Voice_Telephone: 508-548-8700 x2348
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: bandrews@usgs.gov
Process_Step:
Process_Description:
Edits to the metadata were made to fix any errors that MP v 2.9.30 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 format of the time period of content and some process dates had to be fixed. This file had a source contribution, but no other source information. This information had to be modified to meet the standard. The distribution format was modified in an attempt to be more consistent with other metadata files of the same data format. 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: 20151120
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
Address: 384 Woods Hole Rd.
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543
Contact_Voice_Telephone: 508-548-8700 x2251
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: vatnipp@usgs.gov
Process_Step:
Process_Description:
Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog.
Process_Date: 20170214
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: 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: 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
