Attribute_Accuracy_Report:
The accuracy of the data is determined during data collection. This dataset is derived from a single field survey using identical equipment, set-ups, and staff; therefore, the dataset is internally consistent. During mobilization, each piece of equipment is isolated to obtain internal and external offset measurements with respect to the survey mount. All the critical measurements are recorded manually and digitally entered into their respective programs. For single-beam soundings, the distance between the transducer and the GPS antenna was measured for each personal watercraft and accounted for during post-processing. For ground-based measurements, elevation between the ground and antenna was measured for each surveyor in a walking stride and accounted for during post-processing. For the base stations, the Ashtech ProFlex 500 system has a long static horizontal accuracy of 0.3 centimeters (cm) and 0.6 cm vertical accuracy. For the rovers, the post-processed kinematic horizontal instrument accuracy is 1 cm, and vertical accuracy is 2 cm. The Echotrac CV100 Digital Hydrographic Echo Sounder has a vertical accuracy of 0.01 m +/- 0.1% depth.
The U.S. Geological Survey St. Petersburg Coastal and Marine Science Center collected shallow water bathymetric data of the shoreface and the wilderness breach on Fire Island, New York, in June 2014.
This zip archive contains a 50-m gridded digital elevation model (DEM) from June 2014 bathymetry data collected along the shoreface. Users are advised to read online Data Series and the rest of the metadata record carefully for additional details.
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
The digital elevation model (DEM) uncertainty was determined by withholding 10% of the x,y,z bathymetric data points used to create the raster. The raster was then sampled at the withheld positions and a root mean square (RMS) error was calculated from the differences between sample and interpolated bathymetry. The horizontal uncertainty is assumed to be half the vertical uncertainty.
Quantitative_Horizontal_Positional_Accuracy_Assessment:
Horizontal_Positional_Accuracy_Value: 7.0 cm
Horizontal_Positional_Accuracy_Explanation: DEM uncertainty was determined using ArcGIS and Matlab R2015b.
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report:
The DEM uncertainty was determined by withholding 10% of the x,y,z bathymetric data points used to create the raster. The raster was then sampled at the withheld positions and a RMS error was calculated from the differences between sample and interpolated bathymetry.
Quantitative_Vertical_Positional_Accuracy_Assessment:
Vertical_Positional_Accuracy_Value: 14.0 cm
Vertical_Positional_Accuracy_Explanation:
Raster uncertainty was determined using ArcGIS and Matlab R2015b.
Process_Step:
Process_Description:
GPS Acquisition: GPS base stations were erected at benchmarks REST (near the town of Robins Rest) and U374 (NGS benchmark Permanent Identification number (PID#) KU0206) located on Fire Island. Base stations were equipped with Ashtech ProFlex 500 Global Navigation Satellite System (GNSS) receivers. The survey personal watercraft (PWC) (rovers) were equipped with ProFlex 500 GNSS receivers. The base and rover receivers recorded their positions concurrently at 10 Hertz (Hz) throughout the survey. Reference stations coordinates were verified with Continuously Operating Reference Station (CORS) sites using the Online Positioning User Service (OPUS), available at
http://www.ngs.noaa.gov/OPUS/). U374 used reference stations ZNY1, NYRH, CTDA, while REST used stations NYCI, NYRH, and MOR6. OPUS computed both reference stations had horizontal errors of 0.4 cm and vertical errors of 0.2 cm.
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:
U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
Contact_Person: Mark E. Hansen
Contact_Position: Oceanographer
Contact_Address:
Address_Type: mailing and physical address
Address: 600 4th St. S
City: Saint Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727-502-8036
Contact_Facsimile_Telephone: 727-502-8182
Contact_Electronic_Mail_Address: mhansen@usgs.gov
Process_Step:
Process_Description:
Single-Beam Sounding Acquisition: The single-beam bathymetric data were collected on two Yamaha (2010 and 2013) VX Deluxe personal watercraft. Each PWC was fitted with a single-beam transducer below the waterline off the starboard stern, 1.11 m beneath the GPS antenna position. HYPACK version 2013 was used for positioning and navigation during the survey. Depth soundings were recorded at 10 Hertz (Hz) using an Odom Ecotrac CV-100 Digital Hydrographic Echo Sounder system with 200 kHz transducers with 4-degree (10 June 2014) and 9-degree (remainder or survey) transducers. Soundings were merged into a raw data file (.raw) and a sounding file (.bin) in Hypack. Each file was named according to transect number and coordinated universal time (UTC). Water column sound velocity measurements were collected periodically throughout the survey, using a SonTek CastAway conductivity, temperature, and depth (CTD). Data were processed using SonTek CastAway CTD software version 1.5.
Process_Date: 2014
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:
U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
Contact_Person: Billy J. Reynolds
Contact_Position: Engineering Technician
Contact_Address:
Address_Type: mailing and physical address
Address: 600 4th St. South
City: Saint Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727-502-8067
Contact_Facsimile_Telephone: 727-502-8181
Contact_Electronic_Mail_Address: breynolds@usgs.gov
Process_Step:
Process_Description:
Single-Beam Differentially Corrected Navigation Processing: Horizontal positions and vertical elevations associated with each single-beam sounding were post-processed using differential corrections derived from the base/rover setup. Two GPS reference stations were used for the survey and were located at benchmarks "U374" and "REST". Applying the reference station coordinates, GPS data acquired from the rover were processed to the concurrent GPS session data at the base station- using GrafNav version 8.5 software (Waypoint Product Group). The horizontal and vertical coordinates were recorded in the World Geodetic System of 1984 (WGS84) reference frame and exported as an ASCII file for each personal watercraft and each survey day.
Process_Date: 2014
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Mark E. Hansen
Contact_Position: Oceanographer
Contact_Address:
Address_Type: mailing and physical address
Address: 600 4th St. South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727-502-8036
Contact_Facsimile_Telephone: 727-502-8182
Contact_Electronic_Mail_Address: mhansen@usgs.gov
Process_Step:
Process_Description:
Single-Beam Data Processing: Single-beam soundings were merged with differentially processed GPS data and sound velocity profiles using Matlab R2014b. Each transect was visually inspected for elevation outliers and dropouts associated with wave breaking in the surf zone were manually corrected. Typically, the highest intensity return is generated by the seafloor surface. Breaking waves in the surf zone can create air bubbles in the water column and create an erroneous peak in waveform intensity, which causes errors in the interpreted seafloor reflection. When this situation was suspected, a corrected seafloor elevation was manually digitized by analyzing the complete waveform signal recorded by the Odom within the .bin data file. The soundings were corrected for the average speed of sound (table 1). A moving average filter was applied to the soundings to reduce instrument noise and the noise associated with the pitch and roll of the PWC. The depth soundings (from the transducer to the seafloor) were then adjusted to the depth from the GPS antenna and subsequently to the WGS84 ellipsoid.
Process_Date: 2014
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:
U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
Contact_Person: Timothy R. Nelson
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 600 4th St. South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727-502-8098
Contact_Facsimile_Telephone: 727-502-8182
Contact_Electronic_Mail_Address: trnelson@usgs.gov
Process_Step:
Process_Description:
Single-Beam Datum Transformation: NOAA's VDatum v3.3 was used to transform single-beam data points(x,y,z data) from their data acquisition datum (WGS84) to the North American Datum of 1983 (NAD83) reference frame and the North American Vertical Datum of 1988 (NAVD88) elevation using the National Geodetic Survey (NGS) geoid model of 2012A (GEOID12A). For conversion from the WGS84 ellipsoid to NAVD88 there is a total of 5.4 cm of uncertainty in the transformation (
http://vdatum.noaa.gov/docs/est uncertainties.html).
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Timothy R. Nelson
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 600 4th St. South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727-502-8098
Contact_Facsimile_Telephone: 727-502-8182
Contact_Electronic_Mail_Address: trnelson@usgs.gov
Process_Step:
Process_Description:
Single-Beam Error Analysis: The accuracy of the single-beam soundings was evaluated by identifying locations where survey track lines crossed and soundings from each line were horizontally within 0.25 m of each other. Any track line with a root mean square (RMS) error of 12.2 cm for a total of 732 crossings. Since the mean error between wave runners was 0.5 cm, which is below the minimum resolution of the echosounder, no correction offset was applied to the individual echosounders. Applying the square root of the sum of the datum conversion uncertainty and the sounding uncertainty resulted in a combined vertical error of 13.3 cm. Horizontal uncertainty is assumed to be half of the vertical uncertainty (6.7 cm) at most.
Process_Date: 2015
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:
U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
Contact_Person: Timothy R. Nelson
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 600 4th St. South
City: Saint Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727-502-8098
Contact_Facsimile_Telephone: 727-502-8182
Contact_Electronic_Mail_Address: trnelson@usgs.gov
Process_Step:
Process_Description:
Merging Transects: Using Matlab R2015b, partial lines (the result of restarting the line in the middle of a transect) were subsequently merged with similar segments to create one seamless line. When repeats were present, only a single line was retained. The data were then combined into a single ASCII file consisting of position, elevation, line number, vessel number, and time of sampling.
Process_Date: 2015
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Timothy R. Nelson
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 600 4th St. South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727-502-8098
Contact_Facsimile_Telephone: 727-502-8182
Contact_Electronic_Mail_Address: trnelson@usgs.gov
Process_Step:
Process_Description:
Extract Shoreface XYZ: Single-beam x,y,z data were imported into Esri’s ArcGIS version 10.2.2 using the “create feature class from xy table” tool, in ArcCatalog. Using ArcMap polygon was then created surrounding data points within the shoreface of Fire Island in ArcMap. The polygon vertices were converted to points using the “feature vertices to points” tool, “add xy coordinates” tool, and exported as an ASCII file using the “export feature attribute to ASCII” tool. This ASCII file was subsequently imported into Matlab R2015a. Any single-beam data within or on this polygon was then extracted and saved as an ASCII file.
Process_Date: 2015
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Timothy R. Nelson
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 600 4th St. South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727-502-8098
Contact_Facsimile_Telephone: 727-502-8182
Contact_Electronic_Mail_Address: trnelson@usgs.gov
Process_Step:
Process_Description:
Create Digital Elevation Model: The shoreface single-beam x,y,z data were imported into ArcGIS using the "create feature class from xy table" tool in ArcCatalog. The dataset was then subsampled using the "subset features" and 10 percent of the data was removed to provide an estimate of the bathymetry uncertainty. The remaining 90 percent of the dataset was used to create a triangulated irregular network (TIN) using the "create TIN" tool. The TIN was subsequently converted into a raster file using the "TIN to Raster" tool with a cell size of 50 meters. The raster was exported as an ASCII file using the "ASCII to Raster" tool.
Process_Date: 2015
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Timothy R. Nelson
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 600 4th St. South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727-502-8098
Contact_Facsimile_Telephone: 727-502-8182
Contact_Electronic_Mail_Address: trnelson@usgs.gov
Process_Step:
Process_Description:
Remove Extrapolated Cells: The Raster ASCII file was imported into Matlab 2015b and any interpolated grid cells that were more than two cell sizes (100 m) away from a shoreface data point were set to "Not a Number" (NaN). The raster data was then exported as an ArcGIS ASCII file from Matlab R2015b and imported into ArcMap using the "ASCII to Raster" tool.
Process_Date: 2015
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Timothy R. Nelson
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 600 4th St. South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727-502-8098
Contact_Facsimile_Telephone: 727-502-8182
Contact_Electronic_Mail_Address: trnelson@usgs.gov
Process_Step:
Process_Description:
Evaluate Digital Elevation Model Uncertainty: The raster was sampled at the positions of the 10 percent removed data using the "extract values to points" tool and a .csv file was saved from each data table for the personal watercraft and backpack data. Using Matlab R2015b, the sampled data were compared to the subset data and the root mean square differences were calculated. The vertical RMS error was found to be 14 cm.
Process_Date: 2015
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Timothy R. Nelson
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 600 4th St. South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727-502-8098
Contact_Facsimile_Telephone: 727-502-8182
Contact_Electronic_Mail_Address: trnelson@usgs.gov
Process_Step:
Process_Description:
Convert Raster Format: In ArcCatalog(TM), a raster dataset was created using the "create raster dataset" tool with a .tif image format, 64-bit pixel type. The shoreface raster was then imported into this dataset using the "mosaic" tool.
Process_Date: 2015
Source_Produced_Citation_Abbreviation: 201406_Shoreface_DEM.tif
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Timothy R. Nelson
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 600 4th Street South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727-502-8098
Contact_Facsimile_Telephone: 727-502-8182
Contact_Electronic_Mail_Address: trnelson@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
