Parent Layer: Lakebed Surface

Name: Lakebed Backscatter

Display Field:

Type: Raster Layer

Geometry Type: null

Description: <DIV STYLE="text-align:Left;font-size:12pt"><DIV><DIV><P><SPAN>During July-September 2020, Cardinal Point Captains (CPC) hydrographers conducted hydrographic survey operations in three survey areas located on the western side of Bayfield Peninsula in southwestern Lake Superior. Survey operations took place over three legs: Leg 1 (7/25-8/5), Leg 2 (8/25-9/2), and Leg 3 (9/16-9/28). CPC utilized the Research Vessel (R/V) </SPAN><SPAN STYLE="font-style:italic;"><SPAN>Echo</SPAN></SPAN><SPAN><SPAN>, which was equipped with a Teledyne-Reson SeaBat 7125 multibeam echosounder for simultaneously acquiring bathymetry and acoustic backscatter imagery. During survey operations, DEA provided remote technical support to assist CPC with vessel setup, system calibrations, and initial hydrographic data testing and quality control, and coordinated transfers of raw hydrographic data. </SPAN></SPAN></P><P><SPAN /><SPAN /></P><P STYLE="margin:0 0 0 0;"><SPAN>After initial data assessments were complete, the raw multibeam data were prepared for import into CARIS Hydrographic Information Processing System (HIPS) software (version 11.3.8). Upon import into CARIS HIPS software, the raw multibeam data were converted from native Teledyne-Reson s7k file format into CARIS HDCS format. The converted multibeam data were stored logically by survey day. </SPAN></P><P STYLE="margin:0 0 0 0;"><SPAN /><SPAN /></P><P STYLE="margin:0 0 0 0;"><SPAN>After position, motion, waterline, and sound velocity corrections were applied, soundings were gridded for review and directed editing. Preliminary grid resolution was 2 meters (m). Review of bathymetric data was conducted by reviewing multiple bathymetry child layers (e.g. standard deviation, density) in CARIS HIPS and using editing and QC tools to view and edit erroneous soundings (“fliers”), systematic biases, timing errors, or alignment offsets. Upon completion of directed editing, soundings were gridded at 2m and interpolated using the ArcGIS Focal Statistics tool for geospatial analysis. </SPAN></P><P><SPAN /></P><P><SPAN>Acoustic backscatter mosaics are an important piece of information when characterizing surficial seafloor features and delineating benthic habitats.</SPAN><SPAN> After completion of bathymetric data processing, review, and analysis, multibeam backscatter imagery processing was conducted using Quality Positioning Systems (QPS) Fledermaus Geocoder Toolbox (FMGT) software (version 7.9.3). Processed bathymetry data files were exported from CARIS HIPS as Generic Sensor Format (GSF) files. The FMGT workflow paired each native sonar file (Teledyne-Reson s7k format) with its processed GSF file, thus incorporating corrected position and motion data. A beam pattern correction was computed and applied to remove angular bias from the backscatter imagery. Angle Varying Gain (AVG) was applied using the standard “Flat” algorithm and window size of 300 pings. A backscatter imagery mosaic was produced using standard line weighting procedures. The backscatter mosaic was then reviewed manually for motion artifacts and/or brightness offsets. Manual editing was performed to adjust brightness values between adjacent survey lines and/or survey days using the “Head Bias” tool in QPS FMGT software. After the completion of backscatter data processing and quality review, final backscatter image mosaics were produced with pixel resolutions of 1m (as per project specifications) and 2m (Figure 4), the recommended product resolution based on sounding density. The backscatter imagery mosaics were exported in Geotiff format. The backscatter imagery mosaics are referenced to NAD83 UTM Zone 15 North with horizontal units in meters. Backscatter intensity is shown in logarithmic units of decibels (dB). </SPAN></P></DIV></DIV></DIV>

Copyright Text: David Evans and Associates Inc. (DEA), Woolpert, Inc., Cardinal Point Captains (CPC), National Oceanic Atmospheric Administration (NOAA), National Centers for Coastal Ocean Science (NCCOS), Great Lakes Research Initiative (GLRI).

Default Visibility: false

MaxRecordCount: 0

Supported Query Formats: JSON, geoJSON, PBF

Min Scale: 0

Max Scale: 0

Supports Advanced Queries: false

Supports Statistics: false

Has Labels: false

Can Modify Layer: false

Can Scale Symbols: false

Use Standardized Queries: true

Supports Datum Transformation: true

Extent:

XMin: -1.0152031499500452E7
YMin: 5917431.23110754
XMax: -1.0127153499500448E7
YMax: 5938601.231107545
Spatial Reference: 102100  (3857)

Drawing Info:

N/A

Advanced Query Capabilities:

Supports Statistics: false
Supports OrderBy: false
Supports Distinct: false
Supports Pagination: false
Supports TrueCurve: true
Supports Returning Query Extent: true
Supports Query With Distance: true
Supports Sql Expression: false
Supports Query With ResultType: false
Supports Returning Geometry Centroid: false
Supports Binning LOD: false
Supports Query With LOD Spatial Reference: false

HasZ: false

HasM: false

Has Attachments: false

HTML Popup Type: esriServerHTMLPopupTypeNone

Type ID Field: null

Fields: None


Supported Operations:   Query   Query Attachments   Query Analytic   Generate Renderer   Return Updates

  Iteminfo   Thumbnail   Metadata