Identification_Information: Citation: Citation_Information: Originator: Bradford Butman Originator: Page C. Valentine Originator: William W. Danforth Publication_Date: 2007 Title: MB_BATHY20M - 20-m resolution grid of multibeam bathymetry in Massachusetts Bay Edition: 1.0 Geospatial_Data_Presentation_Form: raster digital data Series_Information: Series_Name: Data Series Issue_Identification: 99 Publication_Information: Publication_Place: Woods Hole Science Center, Woods Hole, MA Publisher: U.S. Geological Survey, Coastal and Marine Geology Program Online_Linkage: http://pubs.usgs.gov/ds/99/massbay_gis/2_multibeam/grids/mb_bathy20m.zip Online_Linkage: http://pubs.usgs.gov/ds/99/webpages/massbay.html Larger_Work_Citation: Citation_Information: Originator: Butman, Bradford Originator: Valentine, Page C. Originator: Middleton, Tammie J. Originator: Danforth, William W. Publication_Date: 2007 Title: A GIS Library of Multibeam Data for Massachusetts Bay and the Stellwagen Bank National Marine Sanctuary, Offshore of Boston, Massachusetts Edition: 1.0 Series_Information: Series_Name: Data Series Issue_Identification: 99 Publication_Information: Publication_Place: Woods Hole Science Center, Woods Hole, MA Publisher: U.S. Geological Survey, Coastal and Marine Geology Program Online_Linkage: http://pubs.usgs.gov/ds/99/ Description: Abstract: The U.S. Geological Survey has conducted geologic mapping to characterize the sea floor offshore of Massachusetts. The mapping was carried out using a Simrad Subsea EM 1000 Multibeam Echo Sounder on the Frederick G. Creed on four cruises conducted between 1994 and 1998. The mapping was conducted in cooperation with the National Oceanic and Atmospheric Administration (NOAA) and with support from the Canadian Hydrographic Service and the University of New Brunswick. The long-term goal of this mapping effort is to produce high-resolution geologic maps and a Geographic Information System (GIS) project that presents images and grids of bathymetry, shaded relief bathymetry, and backscatter intensity data from these surveys that will serve the needs of research, management and the public. Purpose: This ESRI grid contains multibeam bathymetry data in Massachusetts Bay This ESRI grid contains multibeam bathymetry data in Massachusetts Bay (covering western Massachusetts Bay map quadrangles 1-3 and Stellwagen Bank National Marine Sanctuary map quadrangles 1-18) at 20 meter resolution. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 1994 Ending_Date: 1998 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -70.900120 East_Bounding_Coordinate: -70.033407 North_Bounding_Coordinate: 42.800047 South_Bounding_Coordinate: 42.083422 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: oceans Theme_Keyword: oceans and estuaries Theme_Keyword: oceans and coastal Theme_Keyword: elevation Theme_Keyword: imageryBaseMapsEarthCover Theme: Theme_Keyword_Thesaurus: General Theme_Keyword: bathymetry Theme_Keyword: multibeam Theme_Keyword: grid Theme_Keyword: 20-m grid Theme_Keyword: sea floor Theme_Keyword: sea floor mapping Theme_Keyword: USGS Map I-2734 Theme_Keyword: Simrad Theme_Keyword: EM 1000 Theme_Keyword: Frederick G. Creed Theme_Keyword: Woods Hole Science Center Theme_Keyword: WHSC Theme_Keyword: Coastal and Marine Geology Program Theme_Keyword: CMGP Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Place: Place_Keyword_Thesaurus: General Place_Keyword: Massachusetts Place_Keyword: Massachusetts Bay Place_Keyword: Boston Place_Keyword: Stellwagen Basin Place_Keyword: Stellwagen Bank Place_Keyword: Stellwagen Bank National Marine Sanctuary Place_Keyword: SBNMS Place_Keyword: Jeffreys Ledge Place_Keyword: MWRA ocean outfall Place_Keyword: MWRA Place_Keyword: Massachusetts Bay Disposal Site Place_Keyword: MBDS Place_Keyword: Tillies Bank Place_Keyword: Gulf of Maine Place_Keyword: United States Place_Keyword: North Atlantic Ocean Access_Constraints: None Use_Constraints: These data are not to be used for navigation purposes. Mariners should refer to the appropriate nautical chart. Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Bradford Butman Contact_Position: Oceanographer 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 x2212 Contact_Facsimile_Telephone: (508) 457-2309 Contact_Electronic_Mail_Address: bbutman@usgs.gov Hours_of_Service: 8 a.m. - 5 p.m. Native_Data_Set_Environment: Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.1.0.780 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: No attributes are associated with these data. Completeness_Report: These data were corrected for tidal elevation using the NOAA Boston tide gage. This assumes that the tidal elevation and phase are the same as Boston across the survey area. Further processing to correct for the spatial and temporal changes in tidal elevation across the survey area may be undertaken at a later time. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: These data were navigated with a Differential Global Positioning System (DGPS); they are accurate to +/- 3 meters, horizontally. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: These data have been corrected for vessel motion (roll, pitch, heave, yaw) and tidal offsets, and referenced to mean lower low water. The theoretical vertical resolution of the Simrad EM-1000 multibeam echosounder is 1 % of water depth, approximately 0.3 - 1.0 m within the study area. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: Unpublished Material Title: Multibeam bathymetric survey data collected by USGS in Massachusetts Bay, 1994-1998 Geospatial_Data_Presentation_Form: raster digital data Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 1994 Ending_Date: 1998 Source_Currentness_Reference: ground condition Process_Step: Process_Description: Data acquisition at sea These multibeam data were collected with a Simrad EM1000 multibeam echo sounder mounted on the starboard pontoon of the Canadian Hydrographic Service Vessel Frederick G. Creed. The data were collected over four cruises carried out between the fall of 1994 and fall of 1998. Operation of the Simrad EM1000 was carried out by hydrographers of the Canadian Hydrographic Service. Data were collected along tracklines spaced 5-7 times the water depth apart at a speed of 10-14 knots. The frequency of the sonar was 95kHz. Sound velocity profiles were obtained and input into the Simrad processing system to correct for refraction. Navigation was by means of differential GPS. Process_Date: Unknown Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: William Danforth Contact_Organization: U.S. Geological Survey Contact_Position: Operational Geologist 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 x2274 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: bdanforth@usgs.gov Hours_of_Service: 8 a.m. to 5 p.m. EST Process_Step: Process_Description: Data processing and editing at sea Processing of the data was carried out by USGS personnel with assistance from the Ocean Mapping Group at the University of New Brunswick (UNB), Canada. A suite of processing software (called swathed) developed by the Ocean Mapping Group () was used to process, edit, and archive the bathymetric soundings. The processing and editing steps carried out on board the ship were: 1.. Demultiplex (unravel) the Simrad data files using RT to generate separate files for a given raw file (filename.raw_all) containing navigation (filename.nav), depth soundings (filename.merged), sidescan sonar backscatter values (filename.merged_ssdata), acquisition parameters (filename.param) sound velocity at the transducer (filename.sv_tdcr) and sound velocity profiler information (filename.svp). Command line: RT -packdown -background -WRITE -em1000 -CnC -prefix RawFiles/ -suffix _raw.all -out ProcessedFiles/InputFilenamePrefix InputFilenamePrefix 2. Edit the navigation data on-screen using the SwathEd routine jview to remove undesirable points, including turns at the ends of survey lines. Jview also rejects stray GPS fixes outside of the survey area, as set by the operator. Command line: jview -rejectnav -navedit filename.nav MassbayMap.sun_315 3. Edit the multibeam soundings for each trackline. SwathEd displays blocks of data across and along the trackline. Anomalous points were identified by comparison to other points and by an understanding of the sea floor geology and morphology. Anomalous soundings were removed. Command line: swathed filename.merged 4. Map the bathymetric soundings from each processed data file onto a Mercator grid or DTM using weigh_grid with grid nodes spaced at 20 meters. The weigh_grid program creates a DTM by summing up the weighted contributions of all the provided data into the DTM. The weighted contributions only extend to a user defined region around the true location of the estimate (the cutoff). The weight of an individual point contribution decays away from the node location based on the order of the Butterworth (inverse weighting) filter (-power n), the width of the flat topped radius of the weighting function (-lambda n.n), and the absolute cutoff limit (-cutoff) that will be used for data points contributing to a node. In addition, each beam/other value can be pre-weighted if required to account for its reliability. A custom weight file for each beam is created by hand and input into the weigh_grid program using the -custom_weight option. Three files are created which are used by the weigh_grid program. An ".r4" file, which contains the grid node values in binary format, an "r4_weights" file, and an "r4_weight_depth" file. To do the summing of the weights, the .r4_weights file contains the sums of the weights for each data point contributing to the node, and the .r4_weight_depth file contains the sum of the weights x the depths. Naturally the solution is: weight_depth/weights for each node. For more information, visit the OMG website at . First a blank binary grid and the weights and weight_depth files must be created: Command line: make_blank -float gridFile Command line: tor4 gridFile These two steps create all three files with a gridFile prefix. Next, each individual data file (.merged suffix) is added to the grid using weigh_grid. This grid of western Massachusetts Bay and Stellwagen Bank data were created with a grid node spacing of 20 meters, a cutoff radius of 20 meters, and an inner radius to the weighting function of 10 meters: Command line: weigh_grid -omg -tide -coeffs -mindep -2 -maxdep -800 -beam_mask -beam_weight -custom_weight EM1000_Weights -butter -power 2 -cutoff 20 -lambda 10 gridFile filename.merged Process_Date: Unknown Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: William Danforth Contact_Organization: U.S. Geological Survey Contact_Position: Operational Geologist 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 x2274 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: bdanforth@usgs.gov Hours_of_Service: 8 a.m. to 5 p.m. EST Process_Step: Process_Description: Final data processing and editing Processing was carried out to further edit and correct the data and to produce final grids and images of the data. Processing and editing steps included: 1. Correct errors in soundings due to sound refraction, caused by variations in sound velocity profile, using the SwathEd refraction tool. These artifacts can be recognized in a cross-swath profile of a relatively flat patch of sea floor. When viewing the swath data across a profile, the sea floor will appear to have a "frown" or "smile" when in fact the data should be flat across the profile. Insufficient and/or erroneous sound velocity information, which is usually due to widely spaced or non-existent velocity profiles within an area, results in an under or over-estimate of water depth which increases with distance from the center of the swath. For a discussion of how this effect can be recognized in a swath bathymetric data file, see < http://www.omg.unb.ca/AAAS/UNB_Seafloor_Mapping.html>. 2. Remove erroneous soundings that were not edited in the field using the SwathEd program. 3. Correct the bathymetric data to mean lower low water by subtracting the observed tide at Boston, Massachusetts from the edited bathymetric soundings. This correction assumes that the tidal phase and amplitude are the same as Boston across the survey area. Mean Lower Low Water (MLLW) tidal information was obtained from the NOAA tide server using tide station 8443970 located at Boston, MA (42 degrees 21.3 minutes N, 71 degrees 3.1 minutes W) (http://tidesandcurrents.noaa.gov/). The binary tide file used in the command line below was generated by reformatting the 6 minute tidal information from the NOAA site into a text file that contains Julian Day (DDD) , time (HH MM), and water level height(H.HH) in this format: DDD HH MM SS H.HH. This file was then converted to a binary tide file with: Command line: binTide -year YYYY asciiTideFile BinaryTideFile The program mergeTide brings the swath soundings to the MLLW vertical tidal datum: Command line (tides): mergeTide -tide BinaryTideFile filename.merged Command line (navigation): mergeNav -ahead 5.379 -right 3.851 -below 4.244 filename (prefix only) 4. Create a 10-m grid of the bathymetric soundings for western Massachusetts Bay Quadrangles and Stellwagen Bank using the SwathEd routine weighgrid. Command line: weigh_grid -fresh_start -omg -tide -coeffs -mindep -2 -maxdep -800 -beam_mask -beam_weight -custom_weight EM1000_Weights -butter -power 2 -cutoff 20 -lambda 5 gridFile filename.merged 5. Convert binary bathymetric grid to ESRI ASCII raster format: Command line: r4toASCII gridFile.r4 This creates a file called gridFile.asc. Process_Date: Unknown Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: William Danforth Contact_Organization: U.S. Geological Survey Contact_Position: Operational Geologist 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 x2274 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: bdanforth@usgs.gov Process_Step: Process_Description: Reprocessing to correct projection error An error in the UNB processing software that resulted in the multibeam observations not being properly projected onto a plane was discovered in 2003. These software errors were corrected and the data re-gridded. The data presented here in the Stellwagen Bank region may differ from preliminary versions included in the following publications: Butman, B., and Lindsay, J.A. (Eds.), 1999, A marine GIS Library for Massachusetts Bay: focusing on Disposal sites, Contaminated Sediments, and Sea Floor Mapping: U.S. Geological Survey Open-File Report 99-439, 1 CD-ROM. (Also available on line at http://pubs.usgs.gov/of/of99-439/start.htm) Gutierrez, B.T., Butman, Bradford, and Blackwood, D.S., 2001, Photographs of the sea floor of western Massachusetts Bay, offshore of Boston, Massachusetts, July 1999: U.S. Geological Survey Open-File Report 00-427, 1 CD-ROM. (Also available on line at http://pubs.usgs.gov/of/of00-427/) Valentine, P.C., Middleton, T., and Fuller, S., 2001, Maps showing sea floor topography, sun-illuminated sea floor topography, and backscatter intensity of the Stellwagen Bank National Marine Sanctuary region off Boston, Massachusetts: USGS Open-File Report #00-410, 1 CD-ROM, scale 1:60,000. (Also available on line at http://pubs.usgs.gov/of/of00-410/) Process_Date: Unknown Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: William Danforth Contact_Organization: U.S. Geological Survey Contact_Position: Operational Geologist 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 x2274 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: bdanforth@usgs.gov Process_Step: Process_Description: An ESRI bathymetry grid was created by importing data from ESRI ASCII raster format into ESRI grid format. Process_Date: Unknown Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Tammie Middleton Contact_Position: Operational Geologist 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 Process_Step: Process_Description: Data shifted 1/2 grid cell to northwest (using the ArcMap/Data Management Tools/Projections and Transformations/Raster/Shift tool) to correct for an error identified in the SwathEd gridding algorithm in 2007. Process_Date: 200702 Source_Produced_Citation_Abbreviation: mb_bathy20m Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: William Danforth Contact_Organization: U.S. Geological Survey Contact_Position: Operational Geologist 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 x2274 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: bdanforth@usgs.gov Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Grid Cell Row_Count: 4030 Column_Count: 3610 Vertical_Count: 1 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Map_Projection: Map_Projection_Name: Mercator Mercator: Standard_Parallel: 41.650000 Longitude_of_Central_Meridian: -70.316667 False_Easting: 0.000000 False_Northing: 0.000000 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: row and column Coordinate_Representation: Abscissa_Resolution: 20.000000 Ordinate_Resolution: 20.000000 Planar_Distance_Units: meters 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 Vertical_Coordinate_System_Definition: Depth_System_Definition: Depth_Datum_Name: Mean lower low water Depth_Resolution: 0.5 Depth_Distance_Units: Meters Depth_Encoding_Method: Explicit depth coordinate included with horizontal coordinates Distribution_Information: Distributor: Contact_Information: Contact_Person_Primary: Contact_Person: Bradford Butman Contact_Organization: U.S. Geological Survey Contact_Position: Oceanographer Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: Massachusetts Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: (508) 548-8700 x2212 Contact_Facsimile_Telephone: (508) 457-2309 Contact_Electronic_Mail_Address: bbutman@usgs.gov Hours_of_Service: 8 a.m. to 5 p.m. EST Resource_Description: Downloadable Data Distribution_Liability: Although these data have been used by the U.S. Geological Survey (USGS), U.S. Department of the Interior (DOI), no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. 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: ARCG Format_Version_Number: 9.1 Format_Specification: ESRI raster grid Format_Information_Content: A zip archive containing the ESRI Raster Grid files and metadata. File_Decompression_Technique: zip archive Transfer_Size: 63.225 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://pubs.usgs.gov/ds/99/massbay_gis/2_multibeam/grids/mb_bathy20m.zip Access_Instructions: Data may be downloaded via the World Wide Web. Offline_Option: Offline_Media: DVD-ROM Recording_Capacity: Recording_Density: 4.75 Recording_Density_Units: Gbytes Recording_Format: UDF Fees: None Technical_Prerequisites: These data are available in Environmental Systems Research Institute (ESRI) Raster GRID format. The user must have software capable of importing and processing the data file. Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Information Services Contact_Address: Address_Type: mailing address Address: Box 25286 Denver Federal Center City: Denver State_or_Province: Colorado Postal_Code: 80225-0046 Country: USA Contact_Voice_Telephone: (303) 202-4700 Contact_Facsimile_Telephone: (303) 202-4188 Hours_of_Service: 8 a.m. to 5 p.m. Mountain Time Resource_Description: Downloadable Data Distribution_Liability: Although these data have been used by the U.S. Geological Survey (USGS), U.S. Department of the Interior (DOI), no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. 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: ARCG Format_Version_Number: 9.1 Format_Specification: ESRI raster grid Format_Information_Content: A zip archive containing the ESRI Raster Grid files and metadata. File_Decompression_Technique: zip archive Transfer_Size: 63.225 Digital_Transfer_Option: Offline_Option: Offline_Media: DVD-ROM Recording_Capacity: Recording_Density: 4.75 Recording_Density_Units: Gbytes Recording_Format: UDF Fees: None Technical_Prerequisites: These data are available in Environmental Systems Research Institute (ESRI) Raster GRID format. The user must have software capable of importing and processing the data file. Metadata_Reference_Information: Metadata_Date: 20070327 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Brad Butman Contact_Organization: U.S. Geological Survey Contact_Position: Oceanographer 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 x2212 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: bbutman@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_Access_Constraints: None Metadata_Use_Constraints: None Metadata_Extensions: Online_Linkage: http://www.esri.com/metadata/esriprof80.html Profile_Name: ESRI Metadata Profile