Metadata: Identification_Information: Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: 2017 Title: Chandeleurs_2013_50_NAD83_NAVD88_GEOID09_DEM.tif: 50-Meter Digital Elevation Model (DEM) of Coastal Bathymetry Collected in 2013 from the Chandeleur Islands, Louisiana (U.S. Geological Survey (USGS) Field Activity Numbers (FAN) 13BIM02, 13BIM03, 13BIM04, 13BIM07, and 13BIM08.) Geospatial_Data_Presentation_Form: raster digital data Online_Linkage: http://pubs.usgs.gov/ds/1032/download/raster/Chandeleurs_2013_50_NAD83_NAVD88_GEOID09_DEM.zip Larger_Work_Citation: Citation_Information: Originator: Nancy T. DeWitt Originator: Jennifer L. Miselis Originator: Jake J. Fredericks Originator: Julie C. Bernier Originator: B.J. Reynolds Originator: Kyle W. Kelso Originator: Dave M. Thompson Originator: James G. Flocks Originator: Dana S. Wiese Publication_Date: 2017 Title: Coastal Bathymetry Data Collected in 2013 from the Chandeleur Islands, Louisiana Geospatial_Data_Presentation_Form: multimedia presentation Series_Information: Series_Name: U.S. Geological Survey Data Series Issue_Identification: 1032 Publication_Information: Publication_Place: St. Petersburg, FL Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.3133/ds1032 Description: Abstract: As part of the Barrier Island Evolution Research Project, scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center (SPCMSC) conducted nearshore geophysical surveys around the northern Chandeleur Islands, Louisiana, in July and August of 2013. The objective of the study is to better understand barrier-island geomorphic evolution, particularly storm-related depositional and erosional processes that shape the islands over annual to interannual timescales (1‒5 years). Collecting geophysical data will allow us to identify relationships between the geologic history of the island and its present day morphology and sediment distribution. This mapping effort was the third in a series of three planned surveys in this area. High resolution geophysical data collected in each of three consecutive years along this rapidly changing barrier island system will provide a unique time-series dataset that will significantly further the analyses and geomorphological interpretations of this and other coastal systems, improving our understanding of coastal response and evolution over short time scales (1‒5 years). This data series includes the geophysical data that were collected during two cruises (USGS Field Activity Numbers (FAN) 13BIM02, 13BIM03, and 13BIM04, in July 2013; and FANs 13BIM07 and 13BIM08 in August 2013) aboard the R/V Sallenger, the R/V Jabba Jaw, and the R/V Shark along the northern portion of the Chandeleur Islands, Breton National Wildlife Refuge, Louisiana. Primary data were acquired with the following equipment: (1) a Systems Engineering and Assessment, Ltd., SWATHplus interferometric sonar (468 kilohertz [kHz]), (2) an EdgeTech 424 (424 kHz) chirp sub-bottom profiling system, and (3) two Teledyne Odom Hydrographic Systems, Incorporated, Echotrach CV100 single beam echosounders. This data series report serves as an archive of processed interferometric swath and single-beam bathymetry data. Geographic information system data products include an interpolated digital elevation model, trackline maps, and point data files. Additional files include error analysis maps, Field Activity Collection System logs, and formal Federal Geographic Data Committee metadata. Note: These data are scientific in nature and are not to be used for navigation purposes. Any use of trade names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Purpose: This 50-m cell size DEM is an interpretive product that was derived from the processed single-beam bathymetry (SBB) and interferometric swath bathymetry (IFB) data collected in July and August of 2013 around the northern Chandeleur Islands, Louisiana. Supplemental_Information: Both the single-beam and interferometric swath surveys were acquired and processed to a geodetic reference ellipsoid. The interferometric swath bathymetry navigation data was acquired with Marinestar High Precision (HP) Differential Geographic Positioning System (DGPS), which used the ITRF2005 datum. The single-beam bathymetry data was acquired using real-time kinematics (RTK) for 13BIM03 and 13BIM04 in July. The single-beam bathymetry data for 13BIM08 in August was post-processed to obtain DGPS navigation. Both single-beam surveys were referenced to WGS84 (G1150)/ITRF00. Both SBB and IFB datasets were transformed horizontally to NAD83 and then vertically to NAVD88 using GEOID09 (NOAA NGS VDatum software version 3.3, (http://vdatum.noaa.gov/). The final x,y,z position data from each survey were merged to generate a DEM with a resolution of 50-meter (m) cell size. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20130705 Ending_Date: 20130901 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: none Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -88.916525 East_Bounding_Coordinate: -88.794837 North_Bounding_Coordinate: 30.097294 South_Bounding_Coordinate: 29.933714 Keywords: Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:8a5a414d-50ad-49c5-abf8-41d0a23e51e2 Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: elevation Theme_Keyword: geoscientificInformation Theme_Keyword: imageryBaseMapsEarthCover Theme_Keyword: oceans Theme: Theme_Keyword_Thesaurus: General Theme_Keyword: marine geology Theme_Keyword: bathymetry Theme_Keyword: interferometry Theme_Keyword: swath Theme_Keyword: SEA Swathplus Theme_Keyword: Systems Engineering and Assessment Theme_Keyword: Swathplus 468 kHz Theme_Keyword: CARIS Theme_Keyword: HIPS and SIPS Theme_Keyword: single beam Theme_Keyword: echosounder Theme_Keyword: ODOM Theme_Keyword: ODOM Echotrach CV-100 Theme_Keyword: hydrography Theme_Keyword: geophysical Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Theme_Keyword: Coastal and Marine Geology Program Theme_Keyword: CMGP Theme_Keyword: St. Petersburg Coastal and Marine Science Center Theme_Keyword: SPCMSC Theme_Keyword: Barrier Island Evolution Research Project Theme_Keyword: Barrier Island Mapping Theme_Keyword: 13BIM02 Theme_Keyword: 13BIM03 Theme_Keyword: 13BIM04 Theme_Keyword: 13BIM07 Theme_Keyword: 13BIM08 Place: Place_Keyword_Thesaurus: Geographic Names Information System (GNIS) Place_Keyword: Chandeleur Islands Place_Keyword: Gulf of Mexico Place_Keyword: Chandeleur Sound Place_Keyword: Louisiana Access_Constraints: None Use_Constraints: The U.S. Geological Survey requests that it be referenced as the originator of this dataset in any future products or research derived from these data. These data should not be used for navigational purposes. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Nancy T. DeWitt Contact_Position: Geologist Contact_Address: Address_Type: Mailing and physical Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: (727) 502-8000 Contact_Electronic_Mail_Address: ndewitt@usgs.gov Data_Set_Credit: U.S. Geological Survey, Coastal and Marine Geology Program, St. Petersburg Coastal and Marine Science Center Native_Data_Set_Environment: Microsoft Windows 7 Service Pack 1; ESRI ArcGIS 10.3.1 SP1 (Build 3143) Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The accuracy of the data is determined during data collection. The SBB and IFB data were collected during concurrent research cruises in July and August of 2013. Methods were employed to maintain data collection consistency aboard various platforms. During mobilization, each piece of equipment (SBB and IFB) is isolated to obtain internal and external offset measurements with respect to the survey platform. Each system has a dedicated computer, and efforts are made to utilize the same equipment and software versions on both systems. However, upgrades and changes occur and require additional setup, measurements, and notation. DGPS was always implemented for navigational accuracy either during acquisition or as a post-processing step. These bathymetric data have not been independently verified for accuracy. For the SBB, offsets between the single-beam transducers, the Ashtech antenna reference point (ARP), and the TSS motion unit were measured and accounted for on the rovers. For RTK in July (13BIM03 and 13BIm04) all respective base station parameters and rover parameters including antenna height and antenna models were entered into their respective GPS units. For the August surveys, all pertinent measurements were accounted for in the DGPS post-processing software packages (National Geodetic Survey On-Line Positioning User Service, OPUS, and Waypoint Product Group GrafNav, version 8.3). Bar checks were also performed as calibration efforts and accounted for any drift in the echosounder. For the IFB, offsets between the sonar head and the DGPS antennas were measured and entered into the CodaOctopus F190R internal setup program. DGPS was provided through the Marinestar HP wide-area GPS service. All the critical measurements were recorded manually and digitally and entered into their respective programs for calibration. The CodaOctopus F190R was calibrated daily and survey operation would commence once calibration status was considered completed and acceptable. Logical_Consistency_Report: The SBB and IFB data were collected during concurrent research cruises in July and August 2013. Refer to the online data series linkage for field logs, vessel platform descriptions, and other survey information. This dataset was created to provide a single post-processed DEM from the merged datasets. The DEM is 50-m cell-size resolution; data gaps between acquisition tracklines are predicted values generated by the gridding algorithm. Completeness_Report: This is a completely processed DEM representing an interpolated bathymetric surface derived from the acoustic interferometric swath and single-beam bathymetry data. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: For the single-beam navigation processing, all the static base station sessions were processed through the On-Line Positioning User Service (OPUS) maintained by the National Oceanic and Atmospheric Administration (NOAA) and the National Geodetic Survey (NGS). The base location results from OPUS were entered into a spreadsheet to compute a final, time-weighted positional coordinate (latitude, longitude, and ellipsoid height). Base-station positional error for each GPS session was calculated as the absolute value of the final position minus the session position value. The maximum horizontal error of the base station coordinates used for RTK and or post-processing the SBB was 0.00042 decimal seconds latitude and 0.00096 decimal seconds longitude for the USGS benchmark TMRK, and 0.00015 decimal seconds latitude and 0.00030 decimal seconds longitude for the USGS benchmark BRM2. For the interferometric swath bathymetry data collection horizontal navigational accuracy is a result of the Marinestar HP DGPS. The horizontal accuracy of the Marinestar HP navigation subscription is reported by the service as +/-10 cm (95% of the time), http://www.fugromarinestar.com/Products-Services/Services/Marinestar_GPS. Quantitative_Horizontal_Positional_Accuracy_Assessment: Horizontal_Positional_Accuracy_Value: 0.00000 - 0.00042 Horizontal_Positional_Accuracy_Explanation: latitude decimal seconds Quantitative_Horizontal_Positional_Accuracy_Assessment: Horizontal_Positional_Accuracy_Value: 0.00001 - 0.00096 Horizontal_Positional_Accuracy_Explanation: longitude decimal seconds Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: All static base station sessions for TMRK and BRM2 were processed through On-Line Positioning User Service (OPUS) maintained by the National Oceanic and Atmospheric Administration (NOAA) and the National Geodetic Survey (NGS). The base location results from OPUS were entered into a spreadsheet to compute a final, time-weighted positional coordinate (latitude, longitude, and ellipsoid height). Base-station positional error for each GPS session was calculated as the absolute value of the final position minus the session position value. SPCMSC standards define the maximum acceptable vertical error for any individual base station GPS session as less than or equal to 3 times the standard deviation of the ellipsoid height; any occupations exceeding this error are removed and the base station coordinates are recalculated. For TMRK base location the standard deviation of the ellipsoid height was 0.014 m and the maximum difference from the average ellipsoid for any GPS session was +/- 0.030 m. For BRM2 base location the standard deviation of the ellipsoid height was 0.013 m and the maximum difference from the average ellipsoid for any GPS session was +/- 0.031 m. All the RTK and the post-processed SBB data (x,y,z) for 2013 are referenced to these base station coordinates. The differentially corrected navigation files (base station GPS processed to boat GPS) were exported from GrafNav version 8.4 and then imported into CARIS HIPS and SIPS version 7.1 and merged by time with the HYPACK (version 10.0.5.31) raw data files at which point the soundings are then geometrically corrected for motion and speed of sound. For the single-beam soundings, elevation differences at 320 crossings were within +/- 0.15 m which accounts for 68 percent of the crossings. For the interferometric swath bathymetry data collection the vertical navigational accuracy is a result of the Marinestar HP DGPS. The stated vertical accuracy of the Marinestar HP navigation subscription used during swath bathymetry acquisition is +/-0.15 m (95% of the time), http://www.fugromarinestar.com/Products-Services/Services/Marinestar_GPS. The Coda Octopus F190R IMU, which integrates the Marinestar HP position with motion, measures vessel velocity (+/- 0.014 m/s), roll and pitch (< 0.025 degrees), heading (1-m baseline 0.1 degrees), and heave (5 cm per meter of depth). The vertical accuracy for the SWATHplus-H system varies with depth and across track range. At 57 m it is accurate to 10 cm vertically. Maximum vertical transformation error reported by VDatum is 0.171 m or 17.1 centimeters for eastern Louisiana. The sum of the errors (+/- 0.031 m + +/-0.15 m +0.171 m) in the vertical is equal to +/-.352 m or +/- 35.2 cm. Lineage: Process_Step: Process_Description: GPS Acquisition: A GPS base station was erected at a temporarily installed USGS benchmark (TMRK) located on the sound side of the Chandeleur Islands. A second base station (BRM2) was erected on the furthest northern island providing differential GPS coverage for the survey area within a 15 km radius of either benchmark. GPS receivers recorded the 12-channel full-carrier-phase positioning signals (L1/L2) from satellites via the Thales choke-ring antenna at the base stations. This GPS instrument combination was duplicated on the single-beam survey vessel (rover). The SBB data was acquired using RTK for 13BIM03 and 13BIM04 in July. Both base stations were equipped with a Magellan ProFlex500 GPS receiver, a Thales choke ring antenna, a Pacific Crest ADLP-1 390-430 megahertz (MHz) radio, and a Pacific Crest 5 decibel (dB) high power radio whip antenna. The radio whip antennas were placed onto 10-m collapsible masts providing line of site transmission to the vessels (rovers). The GPS and radio components were duplicated on each vessel. The base stations were set to record internally at a rate greater than or equal to the recording rate of the rovers, in this case 5 Hz. The known coordinates of each base station were entered into the GPS receiver and the RTK corrections were broadcast to the roving GPS receivers via the radio links at 5 Hz. The R/V Jabba Jaw recorded GPS positions at 1 Hz using an Ashtech Z-Xtreme GPS receiver and Thales choke ring antenna. The R/V Shark recorded GPS positions at a rate of 5 Hz using a Magellan ProFlex 800 GPS receiver and Ashtech marine antenna (table 2). For the August SBB surveys (13BIM03) RTK was not used to collect SBB data and all navigation was post-processed to obtain DGPS. The base receivers and the rover receiver recorded their positions concurrently at 1-second (s) intervals throughout the survey. GPS data was acquired and processed in the World Geodetic Datum of 1984 (WGS84) (G1150). Process_Date: 2013 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Nancy T. DeWitt Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: (727) 502-8000 Contact_Electronic_Mail_Address: ndewitt@usgs.gov Process_Step: Process_Description: Single-Beam Bathymetry Acquisition: Depth soundings were acquired aboard the R/V Jabba Jaw and the R/V Shark at 100-milliseconds (ms) using an Odom CV100 echosounder system with a 200 kilohertz (kHz) transducer. Boat motion was recorded on the R/V Jabba Jaw at 50-ms intervals using a Teledyne TSS Dynamic Motion Sensor (TSS DMS-05). The R/V Shark did not record boat motion. To minimize motion errors, the R/V Shark recorded GPS at a high rate (5 Hz) and utilized a short antenna height (lever-arm) in combination with a narrow (4 degree) transducer beam. All sensor data were saved into a single raw data file (.raw) in HYPACK, with each device string referenced by a device identification code and time stamped to Coordinated Universal Time (UTC). Sound velocity measurements were collected using a Valeport mini Sound Velocity Profiler (SVP) to observe changes in water column speed of sound (SOS). Process_Date: 2013 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Nancy T. DeWitt Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: (727) 502-8000 Contact_Electronic_Mail_Address: ndewitt@usgs.gov Process_Step: Process_Description: Swath Bathymetry Acquisition: The IFB data were collected aboard the R/V Sallenger using a SEA SWATHplus-H 468 kHz interferometric sonar system. Boat position and motion were recorded in real-time using a CodaOctopus F190R wetpod inertial measurement unit (IMU) mounted underwater between the transducer heads to minimize lever arm geometry errors between the observed depths and associated vessel motion. Real-time corrected positions were acquired via the use of the Marinestar HP satellite constellation subscription. Marinestar HP position correction data and motion data from the IMU were integrated with interferometric soundings in the SWATHplus software package versions 3.7.17 with positional and calibration offsets pre-defined by a session file (.sxs), allowing for real-time-corrected depths. A Valeport Mini Sound Velocity Sensor (SVS) was attached to the transducer mount and collected continuous speed of sound SOS measurements at the depth of the transducers. These values were directly incorporated into the SWATHplus acquisition software giving real-time speed of sound at the transducer while underway. In addition, a separate sound velocity profiler (Valeport miniSVP) was used to collect speed of sound profiles (water surface to seafloor) at intervals throughout the survey. Prior to deployment, all equipment offsets between the sonar head and the DGPS antennas were surveyed in dry dock with the use of a laser total station. All the critical physical measurements between the DGPS antennas and the IMU were entered into the Coda F190R program for calibration. The CodaOctopus F190R was calibrated daily and survey operation would commence once calibration status was considered completed and acceptable. All critical physical measurements between the transducers and the IMU were entered into the SWATHplus configuration file (.sxs) for IFB acquisition. Process_Date: 2013 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Nancy T. DeWitt Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: (727) 502-8000 Contact_Electronic_Mail_Address: ndewitt@usgs.gov Process_Step: Process_Description: Swath Bathymetry Processing: Position data recorded by the Coda-Octopus F190R IMU system were corrected in real time via the Marinestar HP DGPS. The IMU also applied real-time motion corrections for heave, roll, and pitch to the vertical component of each position fix. The corrected positions were then integrated with the observed bathymetric values to calculate a final ellipsoid height and position representing the elevation of the seafloor with respect to the geodetic reference frame ITRF08 across the swath range. SWATHplus serves as both an acquisition software and initial processing software. Preliminary roll calibration trackline data were collected and processed using Systems Engineering and Assessment Ltd. SWATHplus and Grid Processor software version 3.7.17. Instrument offset and calibrations values were input into the session file (.sxs) and the raw data files (.sxr) were then processed using the updated system configuration containing roll calibration values, measured equipment offsets, acquisition parameters, navigation and motion from the F190R, SOS at the sonar head, and SVP cast data. Any calibration offsets or acoustic filtering applied in SWATHplus is also written to the processed data file (.sxp). All processed data files were imported into CARIS HIPS and SIPS version 8.1.7, and the original sounding data were edited for outliers using the program's depth filters and reference surfaces. Any remaining outliers were then edited out manually. A CARIS BASE (Bathymetry with Associated Statistical Error) surface with associated CUBE (Combined Uncertainty and Bathymetry Estimator) sample surface was created from the edited soundings dataset. A BASE hypothesis is the estimated value of a grid node representing all the soundings within a chosen resolution or grid-cell size (for example, 5 m) weighted by uncertainty and proximity; giving the final value as a "sample" of the data within the specific grid cell. This algorithm allows for multiple grid-node hypotheses to be verified or overridden by the user, while maximizing processing efficiency. A 5-m resolution CUBE surface was created to perform initial hypothesis editing using the CARIS Subset Editor tool, followed by higher resolution surface detail editing within subset editor. The sample x,y,z data were exported as ASCII text at a 5 x 5-m sample resolution in the ellipsoid datum of ITRF08. Process_Date: 2013 Source_Produced_Citation_Abbreviation: 13BIM02_07_IFB_LEVEL_05_XXX_ITRF08.txt Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Nancy T. DeWitt Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: (727) 502-8000 Contact_Electronic_Mail_Address: ndewitt@usgs.gov Process_Step: Process_Description: Differentially Corrected Navigation Processing: The coordinate values for each of the GPS base stations (TMRK and BRM2) are the time-weighted average of values obtained from the National Geodetic Survey's (NGS) On-Line Positioning User Service (OPUS). Depending on the survey design, the coordinates were utilized either during acquisition to provide RTK navigation, or imported into the post-processing software GrafNav (Waypoint Product Group). For post processing, the kinematic GPS data from the survey vessels were processed to the concurrent GPS data from the base stations. Steps were taken to ensure that the trajectories between the base and rover were clean and resulted in fixed positions. GPS data quality could be monitored and manipulated by analyzing the graphs, trajectory maps, and processing logs that GrafNav produces for each GPS session. If poor GPS data was identified, some common tools used to improve the solution included, but were not limited to, omitting a satellite flagged as poor in health, excluding time-segments with cycle slips, or adjusting the satellite elevation mask angle. The final, differentially-corrected, precise DGPS positions were computed at 1-second (s) intervals for each roving GPS session, and then exported in American Standard Code for Information Interchange (ASCII) text format, which replaced the uncorrected real-time rover positions recorded during acquisition. The GPS data were processed and exported in the World Geodetic System of 1984 (WGS84) (G1150) geodetic datum. For USGS cruises 13BIM03 and 13BIM04, RTK navigation was implemented. The OPUS derived base station coordinates were programed into their respective base station GPS receivers and position corrections were broadcasted via radio link to the roving GPS receivers located on each survey vessel. However, 13BIM04 was ultimately post-processed using GrafNav version 8.50 after identification of some unreliable navigation segments. RTK was not implemented during cruise 13BIM08 so navigation data was post-processed using GrafNav version 8.4 and all pertinent base information details were accounted during processing. Process_Date: 2013 Source_Produced_Citation_Abbreviation: Post-processed differential navigation data for the rover (boat) in ASCII text format. 3 files (forward, reverse, and combined trajectories) are produced for each GPS session file. Process_Step: Process_Description: Single-beam bathymetry processing: All data were processed using CARIS HIPS and SIPS (Hydrographic Information Processing System and Sonar Information Processing System) version 8.1.5. The raw HYPACK (version 10) data files were imported into CARIS, the differentially corrected navigation files were imported using the generic data parser tool within CARIS, and any SVP profile casts were entered and edited using the SVP editor within CARIS. The bathymetric data components (position, motion, depth, and SOS) were then merged and geometrically corrected in CARIS to produce processed x,y,z data. Next, the data were edited for outliers and then further reviewed in the Subset Editor utility for crossing status, and questionable data points or areas. The geometrically corrected point data were then exported as an x,y,z ASCII text file referenced to WGS84(G1150), equivalent to ITRF00, and ellipsoid height in meters. Source_Used_Citation_Abbreviation: Post-processed differential navigation data files and HYPACK RAW bathymetric data in ASCII text format. Process_Date: 2013 Source_Produced_Citation_Abbreviation: 13BIM03_SBB_ITRF00_xyz.zip 13BIM04_SBB_ITRF00_xyz.zip 13BIM08_SBB_ITRF00_xyz.zip Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Nancy T. DeWitt Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: (727) 502-8000 Contact_Electronic_Mail_Address: ndewitt@usgs.gov Process_Step: Process_Description: Datum transformation: Using the transformation software VDatum version 3.3, both the IFB and SBB data were transformed horizontally from their acquisition datums (IBF, ITRF08; SBB, ITRF00) to the North American Datum of 1983 (NAD83) reference frame and the orthometric vertical datum NAVD88 using the National Geodetic Survey (NGS) geoid model of 2009 (GEOID09). Source_Used_Citation_Abbreviation: 13BIM02_07_ITRF08_xyz.txt 13BIM03_SBB_ITRF00_xyz.txt 13BIM04_SBB_ITRF00_xyz.txt 13BIM08_SBB_ITRF00_xyz.txt Process_Date: 2013 Source_Produced_Citation_Abbreviation: 13BIM02_07_NAD83_NAVD88_GEOID09_xyz.txt 13BIM03_SBB_NAD83_NAVD88_GEOID09_xyz.txt 13BIM04_SBB_NAD83_NAVD88_GEOID09_xyz.txt 13BIM08_SBB_NAD83_NAVD88_GEOID09_xyz.txt Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Nancy DeWitt Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: (727) 502-8000 Contact_Electronic_Mail_Address: ndewitt@usgs.gov Process_Step: Process_Description: Gridding Bathymetric data: Using Esri ArcGIS version 10.3.1, the swath and the single-beam elevations were examined for spatial distribution and vertical agreement. After combining the point data (x,y,z) a triangulated irregular network (TIN) was generated. The tin surface and elevation point-shapefile were used in conjunction to visually scan for any remaining discrepancies. Once all data were reviewed, a 50 x 50-m cell resolution DEM was generated using the natural neighbor algorithm in ArcGIS software. A raster mask was created from the polygon survey extent using the ArcGIS "polygon to raster" conversion tool. The DEM was then clipped to the raster mask using the ArcGIS Spatial Analyst "extract by raster mask" tool. To help reduce uncertainty in the final DEM, the ArcGIS Spatial Analyst "neighborhood" low pass raster-data filter was applied. Source_Used_Citation_Abbreviation: 13BIM02_07_NAD83_NAVD88_GEOID09_xyz.txt 13BIM03_SBB_NAD83_NAVD88_GEOID09_xyz.txt 13BIM04_SBB_NAD83_NAVD88_GEOID09_xyz.txt 13BIM08_SBB_NAD83_NAVD88_GEOID09_xyz.txt Process_Date: 2013 Source_Produced_Citation_Abbreviation: Chandeleurs_2013_50_NAD83_NAVD88_GEOID09_DEM.tif Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Nancy DeWitt Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: (727) 502-8000 Contact_Electronic_Mail_Address: ndewitt@usgs.gov Process_Step: Process_Description: Added keywords section with USGS persistent identifier as theme keyword. Process_Date: 20201013 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 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Grid Cell Row_Count: 359 Column_Count: 229 Vertical_Count: 1 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator Universal_Transverse_Mercator: UTM_Zone_Number: 16 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.9996 Longitude_of_Central_Meridian: -87.0 Latitude_of_Projection_Origin: 0.0 False_Easting: 500000.0 False_Northing: 0.0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: row and column Coordinate_Representation: Abscissa_Resolution: 50 Ordinate_Resolution: 50 Planar_Distance_Units: meter Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1983 (NAD83) Ellipsoid_Name: GRS 1980 Semi-major_Axis: 6378137.0 Denominator_of_Flattening_Ratio: 298.257222101 Vertical_Coordinate_System_Definition: Depth_System_Definition: Depth_Datum_Name: North American Vertical Datum 88 (NAVD88) Depth_Resolution: 0.1 Depth_Distance_Units: meter Depth_Encoding_Method: Implicit coordinate Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Nancy T. DeWitt Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: (727) 502-8000 Contact_Electronic_Mail_Address: ndewitt@usgs.gov Resource_Description: Downloadable data Distribution_Liability: This publication was prepared by an agency of the United States Government. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, nor shall the act of distribution imply any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: GeoTIFF File_Decompression_Technique: ZIP Transfer_Size: 0.161 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://pubs.usgs.gov/ds/1032/download/raster/Chandeleurs_2013_50_NAD83_NAVD88_GEOID09_DEM.zip Fees: none Technical_Prerequisites: The raster contained in the .zip file is available as GeoTIFF. To utilize this data, the user must have a GIS software package capable of reading .tif format. Metadata_Reference_Information: Metadata_Date: 20201013 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Nancy T. DeWitt Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical Address: 600 4th Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: 727-502-8000 Contact_Electronic_Mail_Address: ndewitt@usgs.gov Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Use_Constraints: The U.S. Geological Survey requests that it be referenced as the originator of this dataset in any future products or research derived from these data. Metadata_Security_Information: Metadata_Security_Classification_System: None Metadata_Security_Classification: Unclassified Metadata_Security_Handling_Description: None