e032d08fbc0987878a7d2cb1f23ad3c8 English dataset David Gordon Gardline Limited Principle Client Reporting Manager dassh.enquiries@mba.ac.uk pointOfContact 2018-10-10 MEDIN Discovery metadata standard 2.3.8 urn:ogc:def:crs:EPSG::4258 11209 HOW03 GP1B Lot 4 Geophysical UHR Survey 2018 - MBES 2018-09-19 publication 11209 Wind Farm Identifier: HOW03 LOT4; Survey Details: Geophysical 1b pre-geotechnical UXO survey acquiring magnetometer array, bathymetry, side scan sonar, sub bottom profiler, ultra-high resolution multichannel seismic and environmental grab sample data across wind farm and along export cable corridor. Acquired by Gardline Limited. Geophysical Acquisition Dates 2018-05-01 to 2018-09-07. Projection: Horizontal datum: ETRS89 (2018.0) Ellipsoid name: GRS 1980 Coordinate system: UTM 31N Vertical Datum LAT David Gordon Gardline Limited Principle Client Reporting Manager dassh.enquiries@mba.ac.uk originator David Gordon Gardline Limited Principle Client Reporting Manager dassh.enquiries@mba.ac.uk custodian continual Marine Environmental Data and Information Network Elevation Hydrography GEMET - INSPIRE themes, version 1.0 2008-01-06 revision Bathymetry and Elevation SeaDataNet P021 parameter discovery vocabulary 2009-11-16 revision Use of this data requires approval from Orsted otherRestrictions Use of this data requires approval from Orsted English elevation inlandWaters 2.2100 2.7900 53.6900 54.0000 2018-05-01 2018-09-07 26.9800 72.9100 David Gordon Gardline Limited Principle Client Reporting Manager dassh.enquiries@mba.ac.uk distributor dataset Vessel: M.V. Ocean Endeavour. Equipment Type: EM2040D Multibeam Echo Sounder 200/400kHz. Data processing has been carried out using Caris Hips and Sips v. 10.4. Tidal elevations and positioning are derived by post-processing GNSS and motion data logged throughout the survey period to produce a highly accurate vessel position and to recover the full spectrum of motion â?? heave, squat, settlement and tide. The raw GNSS/IMU data is post-processed using Terrapos to achieve a tightly-coupled PPP/INS solution. The Smoothed Best Estimate of Trajectory (SBET) output from Terrapos contains the position and motion data, together with error estimates for the multibeam transducer location. The processed GNSS heights and positions are reported in ETRS89 (2018.0) reference frame, referred to the GRS80 reference ellipsoid, exported from Terrapos. The SBET file is applied to data in Caris on a line by line basis to derive a GNSS tide. This element of the processing essentially removes the measured heave from the bathymetry and substitutes the processed SBET GNSS altitude. The SBET file is output relative to the transducer to ensure heave is computed for this location. In order to correctly compute GNSS tide within Caris, the Reference point to Transducer Z value must be included in the GNSS tide calculation as a height correction. Data were converted from raw format using Caris 10.4. Once converted navigation and attitude data were checked and a smooth applied to the navigation, any spikes were manually removed. Following this, tides were applied to the dataset. Data were then output as Ungridded Soundings XYZ file referenced to LAT and to Ellipsoid. These files were also read into Global Mapper v15 and exported as LAZ files. Bathymetric grids (in XYZ, GeoTIF and FLT format) for Average Value (1.0m and 0.5m resolution), Minimum Value(1.0m, 0.5m and 0.25m resolution), Standard Deviation (1.0m resolution), THU (1.0m resolution) and Density (1.0m resolution) were also produced. Bathymetry contours at 1m interval were generated from the 1.0m average grid. Seabed morphology was also classified using the MBES data; Seabed boundaries are interpreted from the side scan sonar mosaic and then cross-correlated to the bathymetry DTM for a final position. Mapping of the acoustic character of the side scan sonar (low and high reflectivity areas) is used to delineate variations in seabed sediment distribution to illustrate sands or gravelly sands whilst the data were examined for evidence of seabed mobility in the form of ripples, megaripples and sand waves. Classification of seabed sediments was undertaken in line with the Folk classification as stated in â??HOW03_Lot4_FullDeliverablesâ??. Seabed morphology interpreted from bathymetry and side scan sonar data, coupled with seabed photography where taken. Seabed morphology described as featureless, rippled (greater than 0.5m wavelength), megarippled (5m to 25m wavelength) and sand waves (greater than 25m wavelength). Each bedform interpreted has an associated height and crest orientation.