The Delmarva Peninsula is a 220-kilometer-long headland, spit, and barrier island complex that was significantly affected by Hurricane Sandy. A U.S. Geological Survey cruise was conducted in the summer of 2014 to map the inner continental shelf of the Delmarva Peninsula using geophysical and sampling techniques to define the geologic framework that governs coastal system evolution at storm-event and longer timescales. Data collected during the 2014 cruise include swath bathymetry, sidescan sonar, chirp and boomer seismic-reflection profiles, acoustic Doppler current profiler, and sample and bottom photograph data. Processed data in raster and vector format are released for the swath bathymetry, sidescan sonar, and seismic-reflection profiles. More information about the USGS survey conducted as part of the Hurricane Sandy Response-- Geologic Framework and Coastal Vulnerability Study can be found at the project website or on the Woods Hole Coastal and Marine Science Center Field Activity Web pages: https://woodshole.er.usgs.gov/project-pages/delmarva/ and https://cmgds.marine.usgs.gov/fan_info.php?fan=2014-002-FA
This 2-m uninterpolated SwathPlus backscatter image was created from swath interferometric data. These data, although they contain small data gaps, are included in addition to side scan sonar data due to the higher positional accuracy of these data when compared to sidescan backscatter. Backscatter data are useful geophysical datasets for geologic framework studies. These data can be used in conjunction with other geophysical and sample data to identifying sea-floor morphology and sediment texture.
ground condition; data were not collected on 20140702-20140704; 20140709; 20140714-20140715 due to weather
Place_Keyword_Thesaurus:None Place_Keyword:Atlantic Ocean Place_Keyword:Delmarva Peninsula Place_Keyword:Delaware Place_Keyword:Maryland Place_Keyword:Virginia Place_Keyword:Ocean City Place_Keyword:Mid-Atlantic Place_Keyword:Salisbury Place_Keyword:Cape Henlopen Place_Keyword:Rehoboth Place_Keyword:Lewes Place_Keyword:Delaware Bay Place_Keyword:Isle of Wight Place_Keyword:Assateague Island Place_Keyword:Assateague Island National Seashore Place_Keyword:Chincoteague Island Place_Keyword:Chincoteague National Wildlife Refuge Place_Keyword:Chincoteague Inlet Place_Keyword:Chincoteague Bay Place_Keyword:Wallops Island Place_Keyword:Parramore Island Place_Keyword:Hog Island
Not to be used for navigation. 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.
Microsoft Windows Version 7.0 (Build 7601) Service Pack 1; ESRI ArcCatalog 22.214.171.1240
This image represents uninterpolated swath interferometric backscatter data at 2.0 meter resolution. The swath width of the interferometric sonar is limited by water depth and other oceanographic conditions like changes in the speed of sound due to salinity, temperature, and stratification. 100 percent overlap was not achieved in all areas of the survey. Small data gaps exist due to the limited range of the sonar, and these gaps were left unfilled in the mosaic. Trackline artifacts associated with NADIR and acquisition parameters can also be seen in the mosaic.
Survey line bathymetry data that were collected within the Delmarva survey area were incorporated in this grid with the exception of the lines listed below. These lines were left out of the final mosaic either because the data quality were poor, the lines were duplicated or superseded by another line of better data quality, the line was a jog around a shoal and was redundant, or their contribution to the final product was not significant, such as the widely spaced (3 km) boomer seismic lines. l1f1-f3; l2f1-f5; l3f1-f3; l5f3; l4f1-f4; l5f1-f2; l6f1-f2; l7f1-f5; l8f1-f3; l9f1-f3; l10f1-f5;l11f1-f2; l12f1-f3; l13f1-f3; l12f1-f4; l15f1-f3; l16f1-f2; l17f1-f3; l19f1-l19f8; l20f-l20f8; l21f1-f8; l22f1-f7; l23f1-f8; l23f1-f8; l24f1-f7; l25f1-f2 ;l26f; l27f1-f2; l28f1; l29f1-f2; l30f1-f2; l31f1; l32f1-f2; l33f1; l34f1-f2; l35f1;l36f1-f2; l37f1; l38f1-f2; l39f1; l40f1-f3; l41f1;l42f1-f2; l43f1; l44f1-f2; l50f10; l51f1-l5f4; l52f1-l52f2; l100f1-l100f3; l96f1; l103f3; l155f2; l163f3; and t1f1-t13f1.
Navigation was acquired with a Coda Octopus F185 Differential Global Positioning System + Wide Area Augmentation System (DGPS+WAAS), which is accurate to + or - 1 to 2 meters, horizontally and RTK positioning from an Ashtech Proflex 800, which is accurate to less than 1-meter, horizontally. X,Y data are referenced to WGS84. The SWATHPlus transducers were mounted on a rigid pole, approximately 4.195 m below the water line, along the port side of the M/V Scarlett Isabella. The DGPS antenna and an Ashtech ProFlex 800 RTK GPS were located on the same pole approximately 4.6 m above the sea surface. RTCM corrections were being delivered via the web (ethernet) to the Ashtech ProFlex 800 from shore stations in MD and VA (ethernet satellite link is from a KVH Mini-VSAT Broadband receiver). The RTK corrections were passed through to the F185R giving the SWATHplus system kinematic (x,y) positioning accuracy from Julian Day 170 and later. Lines (l1f1-l7f1) collected prior to 20140719 at 12:40:00 UTC were recorded with WAAS-enabled DGPS because the F185 was not receiving RTCM corrections from the Ashtech ProFlex800. Positional offsets from antennae to MRU were corrected within the SWATHPlus acquisition software.
WAAS enabled DGPS accuracy is estimated to be less than 3 m and the accuracy of RTK-GPS is estimated to be less than 1 m.
Originator:U.S. Geological Survey Publication_Date:Unpublished Material Title:raw interferometric data in sxr format Geospatial_Data_Presentation_Form:raster digital data
USGS used a 234 kHz Systems Engineering and Assessment Ltd. (SEA) SWATHplus interferometric sonar (now BathySwath) mounted on the port side of the M/V Scarlett Isabella. The motion reference unit was located on the head of the transducer.
Survey lines were run at an average speed of 5 knots and were spaced 200 m apart in the nearshore. The SEA SWATHplus-M (BathySwath-1) operates at a frequency of 234 kHz and a variable range (increased or decreased manually depending on water depth, but generally 85-100 m on both sides). The system was operated with a transmit power of 80 percent, a transmit length of 43 cycles, and 4096 samples per channel.
Each raw BathySwath bathymetric sonar file (sxr) was imported into SonarWiz version 6.01.0009 software on the M/V Scarlet Isabella for preliminary shipboard processing. Each line received a bottom tracking correction to remove the water column at nadir. SonarWiz has an automatic bottom-tracking algorithm that generally performs well in most coastal settings. Auto tracking parameters for this survey were set to a blanking value of 4; a duration value of 2; and a threshold of 19 with line smoothing turned on. Some lines required further adjustment to the auto bottom tracking delineation, which can be addressed by manually editing the altitude line in SonarWiz. The only gain function applied in SonarWiz during shipboard processing was an empirical gain normalization function (EGN). The Overlap Mode in the SonarWiz project was set to root mean square (RMS), which displays backscatter data in overlapping areas using an RMS adjustment.
The interferometric backscatter mosaic was exported from SonarWiz version 6.01.0026 as an 8-bit GeoTIFF (UTM Zone 18N, WGS 84) at 2-m resolution. High backscatter values are shown by light tones and low backscatter values are shown by dark tones in the imagery. A world file with the same prefix file name and .tfw extension was created in ArcMap version 10.3.1 using EXPORT RASTER WORLD FILE tool.
The online links to the data were updated to reflect the new server hosting the data. Additionally, other small edits could be made to the metadata, such as modifying http to https where appropriate. The metadata date (but not the metadata creator) was edited to reflect the date of these changes.
Contact_Organization:U.S. Geological Survey Contact_Person:VeeAnn A. Cross
There are no attributes associated with a GeoTIFF image. Pixel values for the GeoTIFF have a possible 8-bit pixel range of 0 to 255. However, the acoustic reflectivity data range from 1 to 53. Low-backscatter is represented by dark tones (low values) and high-backscatter is represented by bright tones (high values). In this TIFF format, the NODATA values are represented as NODATA.
USGS data release 2014-002-FA interferometric backscatter from the Delmarva Peninsula area (2014-002-FA_SwathBS.zip). The zip file contains the following a GeoTiff image in BigTIFF format: (2014-002-FA_SwathBS_2m.tif) with a world file (2014-002-FA_SwathBS_2m.tfw). A browse graphic (2014_002_FA_SwathBS_2m_100.png) and FGDC CSDGM metadata files (2014_002_FA_SwathBS_2m.xml) in four standard formats are also included in the zip file.
Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. 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.
Format_Name:GeoTIFF Format_Version_Number:ArcMap version 10.3.1 Format_Specification:GeoTIFF image (BigTIFF format) Format_Information_Content:
The zip file (WinZip v 14.5) contains a folder with a GeoTIFF image at 2-meter resolution and the associated metadata and world files
File_Decompression_Technique:Use WinZip or pkUnzip Transfer_Size:74
The image contained in the ZIP file is available as BigTIFF GeoTIFF image with a world file. To utilize these data, the user must have an image viewer, or an image processing or GIS software package capable of importing a BigTIFF image. This image may not open in older GIS software (earlier than version 10.0)
Contact_Person:Elizabeth A. Pendleton Contact_Organization:U.S. Geological Survey