CatIsland_2010_Bathy_NAVD88_grid.tif

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What does this data set describe?

Title: CatIsland_2010_Bathy_NAVD88_grid.tif
Abstract:
In September and October of 2010, the U.S. Geological Survey (USGS), in cooperation with the Army Corps of Engineers (USACE), conducted geophysical surveys around Cat Island, Miss. to collect bathymetry, acoustical backscatter, and seismic reflection data (seismic-reflection data have been published separately, Forde and others, 2012). The geophysical data along with sediment vibracore data (yet to be published) will be integrated to analyze and produce a report describing the geomorphology and geologic evolution of Cat Island. Interferometric swath bathymetry, and acoustical backscatter data were collected aboard the RV G.K. Gilbert during the first cruise which took place September 7-15, 2010. Single-beam bathymetry was collected in very shallow water around the island aboard the RV Streeterville from September 28 through October 2, 2010 to bridge the gap between the landward limit of the previous cruise and the shoreline. The survey area extended from the nearshore to approximately 5 kilometers (km) offshore to the north, south, and west, and approximately 2 km to the east. This report archives bathymetry and acoustical backscatter data and provides information and mapping products essential for completion of the project goals. The bathymetry will provide elevations and show geomorphic characteristics of the seafloor, while the backscatter and acoustical backscatter imagery will enhance the geomorphic characteristics and give insight to variations of sediment types on the seafloor. This file is the 50-m cell size grid of the combined swath and single-beam bathymetry around Cat Island, Miss.
Supplemental_Information:
Both the single-beam and swath surveys were processed to the ellipsoid. The swath survey used OmniSTAR High Precision for the Differential Geographic Positioning System (DGPS) with a datum of ITRF2005, and the single-beam post-processed DGPS navigation was referenced to WGS84 (G1150). They were both transformed horizontally to WGS84 and vertically to NAVD88 using NOAA NGS VDatum software (http://vdatum.noaa.gov/) before the x,y,z components (meters) from each survey were merged into one dataset. Grid cell size is 50 m.
  1. How might this data set be cited?
    Buster, Noreen A., Pfeiffer, William R., Miselis, Jennifer L., Kindinger, Jack L., Wiese, Dana S., and U.S. Geological Survey, 20110131, CatIsland_2010_Bathy_NAVD88_grid.tif: U.S. Geological Survey Data Series 739.

    Online Links:

    This is part of the following larger work.

    Buster, Noreen A., Pfeiffer, William R., Miselis, Jennifer L., Kindinger, Jack L., Wiese, Dana S., and Reynolds, B.J., 20101001, Bathymetry and acoustic backscatter data collected in 2010 from Cat Island, Mississippi: U.S. Geological Survey Data Series 739, U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -89.206906
    East_Bounding_Coordinate: -89.025717
    North_Bounding_Coordinate: 30.303125
    South_Bounding_Coordinate: 30.156408
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2010
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: raster digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Raster data set. It contains the following raster data types:
      • Dimensions 203 x 1317 x 1, type Pixel
    2. What coordinate system is used to represent geographic features?
      The map projection used is Transverse Mercator.
      Projection parameters:
      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 coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 50
      Ordinates (y-coordinates) are specified to the nearest 50
      Planar coordinates are specified in meters
      The horizontal datum used is D WGS 1984.
      The ellipsoid used is WGS 1984.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257223563.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: North American Vertical Datum of 1988
      Altitude_Resolution: 50
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:
    Cell size of this raster is 50 meters, and each cell has a specific elevation value represented at the center grid node.
    Entity_and_Attribute_Detail_Citation:
    The grid was created by the U.S. Geological Survey using data collected by the U.S. Geological Survey.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Noreen A. Buster
    • William R. Pfeiffer
    • Jennifer L. Miselis
    • Jack L. Kindinger
    • Dana S. Wiese
    • U.S. Geological Survey
  2. Who also contributed to the data set?
    U.S. Geological Survey, Noreen A. Buster, William R. Pfeiffer, Jennifer L. Miselis, Jack L. Kindinger, and Dana S. Wiese
  3. To whom should users address questions about the data?
    U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center
    Attn: Noreen A. Buster
    Geologist
    600 4th Street South
    St. Petersburg, FL
    U.S.

    (727) 803-8747 x3114 (voice)
    nbuster@usgs.gov

Why was the data set created?

This grid is an interpretive product and contains a combination of the processed single-beam and interferometric swath bathymetry data collected around Cat Island, Miss. in September and October 2010 by the U.S. Geological Survey (USGS), St. Petersburg Coastal and Marine Science Center. It serves as the bathymetry part of an archive of data for the entire project.

How was the data set created?

  1. From what previous works were the data drawn?
    grid (source 1 of 1)
    U.S. Geological Survey, 2010, CatIsland_2010_Bathy_NAVD88_grid.

    Type_of_Source_Media: physical model
    Source_Contribution: Single-beam and swath bathymetry
  2. How were the data generated, processed, and modified?
    Date: 12-Apr-2012 (process 1 of 10)
    GPS acquisition: A GPS base station was erected within approximately 20 to 30 km of the survey area on a pre-existing National Geodetic Survey (NGS) benchmark at Point Cadet, Miss. GPS data were recorded using Ashtech Z-Xtreme GPS receivers that record the 12-channel full-carrier-phase positioning signals (L1/L2) from the satellites via the Thales choke-ring antenna. This GPS instrument combination is duplicated on the survey vessel (rover). The base receiver and the rover receiver record their positions concurrently at 1-second (s) recording intervals throughout the survey period. Person who carried out this activity:
    U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    Attn: Noreen A. Buster
    Geologist
    600 4th Street South
    St. Petersburg, FL
    U.S.

    (727) 803-8747 x3114 (voice)
    nbuster@usgs.gov
    Date: 12-Apr-2012 (process 2 of 10)
    Differentially Corrected Navigation Processing: The base station GPS files were corrected using the time-weighted average National Geodetic Survey On-Line Positioning User Service (OPUS) solution coordinates. The final value (WGS84, 1150) was processed to the respective roving survey platform GPS file using GrafNav version 8.10 (Waypoint Product Group). During this process, steps were taken to ensure that the trajectory produced from the base to the rover was clean and produced fixed positions. From these processes a single differentially corrected, precise position at 1-s intervals for each roving GPS session was created for the single-beam bathymetry survey. Person who carried out this activity:
    U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    Attn: Noreen A. Buster
    Geologist
    600 4th Street South
    St. Petersburg, FL
    U.S.

    (727) 803-8747 x3114 (voice)
    nbuster@usgs.gov
    Date: 12-Apr-2012 (process 3 of 10)
    Single-beam bathymetry acquisition: TSS-DMS-05 heave, pitch, and roll compensator. Motion acquisition interval is 0.05 seconds (20 hertz). Scientific grade fathometers used were Marimatech E-SEA-103 and 206. Sounding interval is 0.1 seconds (10 hertz). The boat is navigated and all sensor data acquired using HYPACK surveying software. Person who carried out this activity:
    U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    Attn: Noreen A. Buster
    Geologist
    600 4th Street South
    St. Petersburg, FL
    U.S.

    (727) 803-8747 x3114 (voice)
    nbuster@usgs.gov
    Date: 12-Apr-2012 (process 4 of 10)
    Single-beam bathymetry processing: The DGPS position points processed in GrafNav version 8.10 were parsed into the bathymetric processing software CARIS HIPS and SIPS, version 7.1® using the data parser within the software. The sounding depths were recorded using HYPACK® version 10 and were imported into CARIS. Data were edited for outliers, which were removed and the x,y,z data were exported in their originally acquired ellipsoid datum of WGS84 (1150). The data were later transformed to horizontal and vertical datum WGS84 and NAVD88 using NOAA NGS VDatum software conversion tool. Person who carried out this activity:
    USGS St. Petersburg Coastal and Marine Science Center
    Attn: Noreen A. Buster
    Geologist
    600 4th Street South
    St. Petersburg, FL
    U.S.

    (727) 803-8747 x3114 (voice)
    nbuster@usgs.gov
    Date: 12-Apr-2012 (process 5 of 10)
    Swath bathymetry acquisition: The interferometric swath bathymetry data were collected aboard the RV G.K. Gilbert using a SEA SWATHplus 468 kHz system mounted starboard side with the F190 CodaOctopus (IMU) located between the two transducers with navigation antennas located directly above the transducers on the same mount. Data were acquired with SEA SWATHplus software using an acquisition .sxs file, which included measured equipment offsets, position data from OmniSTAR High Performance GPS service (ITRF 2005), motion data from the CodaOctopus F190 (calibrated in the field prior to the survey), and speed of sound at the transducer head and produced raw .sxr files. Acquisition settings include: Transmit Power, 7 percent; Transmit Pulse Length, 12 cycles; Ping Range, 31 m; Sample Interval, 66.06 samples/m; Receive Length, 2048 samples; and Ping Rate Limit, 50 pings/second. No other bathymetric filters were applied during acquisition. Person who carried out this activity:
    U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    Attn: Noreen A. Buster
    Geologist
    600 4th Street South
    St. Petersburg, FL
    U.S.

    (727) 803-8747 x3114 (voice)
    nbuster@usgs.gov
    Date: 18-Nov-2011 (process 6 of 10)
    Swath Bathymetry processing: SWATHplus is used as the acquisition software and is used in the first step of processing swath data. Roll calibration data were collected and processed using SWATHplus and Grid Processor 3.7.10 (both products of Systems Engineering and Assessment Ltd.). Roll calibration figures were entered into the offsets of the program, and the raw data files (.sxr) were processed using their respective .sxs files, which contain all the survey's measured equipment offsets, acquisition parameters, navigation and motion from the F190R, and speed of sound. During processing, bathymetric filters were applied to raw data to remove noise from the data. Typically, there is one .sxr file for each trackline of data collected, and after processing with filters within SWATHplus the file type output for bathymetric soundings is .sxp. The attitude height derivation was set to combined heave and GPS height, to record data to the ellipsoid height as the acquisition datum for OmniSTAR HP position and navigation is ITRF2005.All .sxp files were imported into CARIS HIPS and SIPS, version 7.1, where the data were edited for outliers using depth filters, reference surfaces, and manual editing of data points. A CARIS BASE (Bathymetry with Associated Statistical Error) surface was created at 10-m resolution for coarse CUBE (Combined Uncertainty and Bathymetry Estimator) surface hypothesis editing in CARIS Subset Editor, and then a 1-m resolution surface was created for detailed editing in subset editor. A CUBE hypothesis surface represents the soundings weighted by uncertainty and proximity to the grid nodes. This algorithm allows for multiple grid node hypotheses to be verified or overridden by the user. The x,y,z data were exported as an ASCII file as a 10 m x 10 m sample of the BASE surface lines in the originally acquired ellipsoid datum of ITRF 2005. The data were then transformed to horizontal and vertical datum WGS84 and NAVD88 using NOAA NGS VDatum software conversion tool. Person who carried out this activity:
    U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    Attn: Noreen A. Buster
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 803-8747 x 3114 (voice)
    nbuster@usgs.gov
    Date: 15-Jan-2012 (process 7 of 10)
    Gridding Bathymetric data: Within ESRI ArcGIS version 10.0.2, the exported CARIS sounding grid points were further investigated for outliers and, if found, were removed. A 50-m cell grid was created using the ArcGIS Topo to Raster tool. In addition to the sounding data, elevation EAARL lidar data (NAVD88) collected for Cat Island by the USGS in 2007 (Smith and others, 2007) were used at 2.5-m resolution. This published dataset was clipped to the published 2007 shoreline file, which was derived from the EAARL lidar at the mean high water mark (Morton and Rogers, 2009; Buster and Morton, 2011). The lidar data were converted from raster to point in ArcGIS and the positive elevation points were used with the bathymetry sounding elevations to create the 50-m grid. A boundary box polygon for the survey extent was also input to Topo to Raster to constrain the outer limits of the grid. Topo to Raster applies the Anudem 4.6.3 algorithm of Hutchinson (1988, 1989). The analysis tool allows the user to input point data, contour data, cell size, land boundaries, data-extent boundaries, shoreline elevation, and a snap raster (ensuring final grid-node placement). A detailed description of the Topo to Raster (Anudem 4.6.3) algorithm can also be found within the help menu of ESRI ArcGIS.
    Date: 14-Feb-2017 (process 8 of 10)
    Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alan O. Allwardt
    Contractor -- Information Specialist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7551 (voice)
    831-427-4748 (FAX)
    aallwardt@usgs.gov
    Date: 26-Mar-2018 (process 9 of 10)
    Keywords section of metadata optimized by adding theme keyword thesauri and associated keywords. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Arnell S. Forde
    Geologist
    600 4th Street South
    St. Petersburg, FL

    727-502-8000 (voice)
    aforde@usgs.gov
    Date: 13-Oct-2020 (process 10 of 10)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    The accuracy of the data is determined during data collection. These datasets are from two separate research cruises. Methods are employed to maintain data collection consistency aboard various platforms. During mobilization, each piece of equipment (single beam and swath) is isolated to obtain internal and external offset measurements with respect to the survey platform. All the critical measurements are recorded manually and digitally and entered into their respective programs for calibration. Once calibration is complete and calibration status is considered acceptable, then survey operations commence. 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. For the single-beam bathymetry, offsets between the single beam transducers and the Ashtech antenna reference point (ARP) were measured and accounted for in post-processing. Bar checks were performed as calibration efforts and accounted for any drift in the Marimatech Echosounder. The Differential Geographic Positioning System (DGPS) was obtained using post-processing software packages (National Geodetic Survey On-Line Positioning User Service (OPUS, and Waypoint software GrafNav, version 8.10). For the swath bathymetry, 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 OmniSTAR High Performance wide-area GPS service. DGPS is always implemented for navigational accuracy either during acquisition or as a post-processing step. These bathymetric data have not been independently verified for accuracy.
  2. How accurate are the geographic locations?
    All static base station sessions were run 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 put in a spreadsheet to compute final values and error analysis. Using the OPUS values for each day and the total time that data were collected each day, the average weighted values were calculated for each day for latitude and longitude (so the longer occupation times held more value than the shorter times). The final value for latitude and longitude was used in GrafNav for the base station value. Error was calculated using UTM output from OPUS (to get error in meters) for each day and was calculated as the absolute value of the final value minus the daily value. For this survey, the maximum horizontal error for the base station used for processing the single-beam bathymetry was 0.6 cm. DGPS navigation for the swath survey used OmniSTAR HP with horizontal accuracy reported by the service as +/- 10 cm (95% of the time).
  3. How accurate are the heights or depths?
    All static base station sessions were run 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 put in a spreadsheet to compute final values and error analysis. Using the OPUS values for each day and the total time data were collected each day, the average weighted values were calculated for each day for latitude and longitude (so the longer occupation times held more value than the shorter times). The final value for latitude and longitude was used in GrafNav for the base station value. Error was calculated using UTM output from OPUS (to get error in meters) for each day and was calculated as the absolute value of the final value minus the daily value. For this survey, the maximum vertical error for the base station used for processing the single-beam bathymetry was 0.6 cm and the sounding vertical error, calculating the mean of 296 crossings, was 5.4 cm.During swath bathymetry acquisition, ship motion was measured using a CodaOctopus Octopus F190R Precision Attitude and Positioning System where vertical accuracy is directly affected by the accuracy of the navigation system (OmniSTAR HP) with horizontal accuracy reported by the service as +/- 10 cm and vertically as +/-15 cm (95% of the time). Vertical accuracy is also dependent upon the SEA SWATHplus sonar system where depth accuracy decreases with increasing horizontal range. The theoretical vertical resolution of the interferomteric swath system is 10 cm for this survey (<57 m water depth). The single-beam survey measured less vertical error (mean crossing error of 5.4 cm) than the swath dataset; therefore, the swath bathymetry was shifted to match the single beam as well as possible. The maximum shift of swath data was 50-cm. The following swath lines were vertically shifted (added) 13 centimeters: 10h14-10h16. The following swath lines were vertically shifted (added) 15 centimeters: 10h10a, 10h21-10h24, 10h47-10h51, 10h60-10h64. The following swath lines were vertically shifted (added) 25 centimeters: 10h17, 10h18b, 10h19, 10h67-10h73, 10h76, 10h77. The following swath lines were vertically shifted (added) 50 centimeters: 10h74-10h75). Reported vertical transformation error by VDatum is 5.4 centimeters.
  4. Where are the gaps in the data? What is missing?
    This is a complete processed, combined swath and single-beam bathymetry surface produced in GeoTIFF format. These data provide surfaces that are interpolated between tracklines, as this survey did not include overlapping data. There are areas within the single-beam coverage that are seen as discontinuous lines and this is directly due to the exclusion of poor data and (or) instrument failures due, in part, to encountering too shallow of water for the boat to acquire data.
  5. How consistent are the relationships among the observations, including topology?
    These datasets were completed on two research cruises over the course of 14 days in 2010. Refer to the FACS logs for respective vessel platforms and survey information. This dataset was created to show the bathymetry from the cruises. The grid is 50-m spacing.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
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.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    600 4th Street South
    St. Petersburg, FL
    U.S.

    (727) 803-8747 (voice)
    nbuster@usgs.gov
  2. What's the catalog number I need to order this data set? Downloadable data
  3. What legal disclaimers am I supposed to read?
    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.
  4. How can I download or order the data?
  5. What hardware or software do I need in order to use the data set?
    This shapefile was created for use with ESRI ArcGIS software. It may also be viewed with ESRI public domain software ArcExplorer or other GIS software capable of importing the data.

Who wrote the metadata?

Dates:
Last modified: 22-Sep-2021
Metadata author:
U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
Attn: Noreen A. Buster
Geologist
600 4th Street South
St. Petersburg, FL
US

(727) 803-8747 x3114 (voice)
nbuster@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/ds-739metadata_bathygrid.faq.html>
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