Logical_Consistency_Report:
EK60 split-beam echo sounder data were collected nearly continuously throughout cruises 2017-001-FA and 2017-002-FA. Several periods of survey hiatus over one hour in duration were as follows: during 2017-001-FA: May 4 (JD124), ~ 15:00 - 16:50 UTC, while the vessel was forced to evacuate the work zone due to military activity; May 5 (JD125), 10:47 UTC - May 8 (JD128) 00:08 UTC, when ROV maintenance and inclement weather caused survey suspension; May 8 (JD128) 04:42 - 06:47 UTC, during multibeam system testing and troubleshooting; and May 10 (JD130), 01:42 - 02:48 UTC, during a high speed transit between survey sites; and during 2017-002-FA: August 27 (JD239) 10:34 - 14:11 UTC, when logging was suspended during early portion of transit to Norfolk, VA due to inclement weather; and August 27 (JD239) 19:30 UTC - August 30 (JD242) 17:37 UTC, while survey was suspended and the vessel was in port due to inclement weather. The shapefile '2017-002-FA_EK60NavPoints_1min.shp' contains the first (1), last (x), and 1-minute interval navigation fixes for each EK60 trackline. The attribute field 'LineName' for each polyline feature in '2017-001-FA_2017-002-FA_EK60Tracklines.shp' matches the name of the corresponding Simrad .raw acquisition file. Filenames are prepended with HRS1704 and HRS1713, the R/V Hugh Sharp field activity designations for 2017-001-FA and 2017-002-FA, respectively. The 'EK60_Image' attribute field corresponds to the PNG profile images in "'2017-001-FA_2017-002-FA_EK60_Images.zip". In some instances one PNG image exists per raw file, in others PNG images represent the concatenation of multiple raw files. In the case of the later, the name of the PNG image indicates the file range included, eg. the image 'HRS1713_-D20170827-T160948.raw...HRS1713_-D20170827-T175301.raw.png' includes all files between times D20170827-T160948 and D20170827-T175301. As such, a single PNG file can be paired with multiple raw files ('LineName') in '2017-001-FA_2017-002-FA_EK60Tracklines.shp'. The Simrad .raw data were converted to PNG format for ease of display. At some points, acquisition setting changes caused the sample rate of the system to change mid file, an issue which the processing software does not handle properly. As a result, some images contain time periods (mostly toward the end of the files) in which the depth scale is incorrect for data after the sample rate change. These instances are easily recognizable and occur in the following image files: HRS1704-D20170511-T163418.raw.png, HRS1713_-D20170827-T004400.raw.png, HRS1713_-D20170827-T091418.raw.png, HRS1713_-D20170831-T084503.raw.png, HRS1713_-D20170831-T091114.raw...HRS1713_-D20170831-T092942.raw.png, HRS1713_-D20170831-T142123.raw...HRS1713_-D20170831-T152501.raw.png, HRS1713_-D20170831-T161756.raw...HRS1713_-D20170831-T174924.raw.png, HRS1713_-D20170901-T094651.raw...HRS1713_-D20170901-T101116.raw.png, HRS1713_-D20170901-T142600.raw.png, HRS1713_-D20170901-T145353.raw...HRS1713_-D20170901-T154042.raw.png, HRS1713_-D20170901-T180509.raw.png, HRS1713_-D20170902-T032448.raw.png, HRS1713_-D20170903-T052420.raw.png, HRS1713_-D20170903-T093726.raw.png, HRS1713_-D20170903-T130223.raw.png, HRS1713_-D20170903-T174447.raw.png, HRS1713_-D20170903-T175310.raw...HRS1713_-D20170903-T195059.raw.png, HRS1713_-D20170904-T151423.raw.png, HRS1713_-D20170905-T202733.raw...HRS1713_-D20170905-T204307.raw.png, HRS1713_-D20170905-T212717.raw.png, HRS1713_-D20170906-T001017.raw.png, HRS1713_-D20170906-T004638.raw...HRS1713_-D20170906-T013455raw.png, HRS1713_-D20170906-T090408.raw...HRS1713_-D20170906-T101128.raw.png, HRS1713_-D20170906-T155534.raw...HRS1713_-D20170906-T162353.raw.png.
Completeness_Report:
All EK60 data collected during the cruises are represented in these data release files, with the exception of those collected during the system calibration procedures conducted on May 3, (JD123) 17:10 - 20:21 UTC and August 25 (JD237) 12:11 - 14:20 UTC, as well as May 4 (JD124) between 10:29 and 17:09 GMT when data were recorded but without navigation due to serial connection problems. PNG images were not produced for some trackline sections where EK60 data was recorded, but the file was very short or the data were considered particularly poor; in these cases 'no image' is entered in the 'EK60_Image' field of '2017-001-FA_2017-002-FA_SB-EK60Tracklines.shp'.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
The Simrad ES38-10 split-beam transducer was mounted in a frame placed inside the retractable keel of the R/V Hugh R. Sharp, which is located approximately amidships on the center line of the vessel. During cruises 2017-001-FA and 2017-002-FA the frame and transducer were mounted in the forward and rear slots of the retractable keel, respectively. Navigation for the EK60 was collected using the ships POS MV inertial navigation system with intermittent success through May 4 (JD124) of 2017-001-FA, but for the remainder of both cruises navigation was collected from a Hemisphere GPS (GPS) receiver with the GPS antenna mounted on the aft 01 dark handrail approximately 4.57 (2017-001-FA) or 3.4 (2017-002-FA) meters aft and 4 meters to port of the ES38-10 transducer. Positioning data were recorded as raw NEMA messages to the Simrad .raw files in the Simrad ER60 (version 2.4.0) acquisition software. GPS horizontal positional accuracy is assumed to be within 3 m; horizontal offsets of the transducer relative to the GPS antenna were not accounted for during processing.
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: unpublished material
Title: raw Simrad EK60 data (.raw)
Geospatial_Data_Presentation_Form: digital data
Type_of_Source_Media: disc
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20170504
Ending_Date: 20170906
Source_Currentness_Reference: ground condition
Source_Citation_Abbreviation: raw Simrad EK60 data
Source_Contribution:
Split-beam echo sounder data were collected using a Simrad EK60 General Purpose Transceiver and ES38-10 split-beam transducer (38 kHz, 10 degree beam width). The ES38-10 transducer was mounted in a frame placed inside the retractable keel of the R/V Hugh R. Sharp, which is located approximately amidships on the center line of the vessel. During cruises 2017-001-FA and 2017-002-FA the frame and transducer were mounted in the forward and rear slots of the retractable keel, respectively. Navigation for the EK60 was initially collected using the ships POS/MV inertial navigation system with intermittent success through May 4 (JD124) of 2017-001-FA, but for the remainder of both cruises navigation was collected using a Hemisphere GPS (GPS) receiver with the GPS antenna mounted on the aft 01 deck handrail approximately 4.57 (2017-001-FA) or 3.4 (2017-002-FA) meters aft and 4 meters to port of the ES38-10 transducer. While underway, the retractable keel was lowered to 1-meter below the hull, resulting in a draft of 5.06 meters below the waterline. Simrad ER60 (version 2.4.3) acquisition software was used to control the EK60 transceiver and digitally log the echogram data and NEMA GPS messages to the Simrad .raw format. Triggering of the EK60 system was slaved to the Reson 7160 MBES while multibeam data were being collected in order to minimize crosstalk between the two instruments, and internally during the remainder of the survey. Data were acquired over record lengths up to 1500 meters (ER60 acquisition software used a constant sound speed of 1494 meters per second for two way travel time to depth conversion) using pulse lengths of 256, 512, and 1204 microseconds with output power ranging between 450 and 1200 Watts. Each of the pulse length used were calibrated using a 60 millimeter copper ball reference sphere prior to survey during each cruise, and the resulting target strength corrections were used to update the beam data.
Process_Step:
Process_Description:
PROCESS STEP 1:
ESP3 (version 1.3.0), Microsoft Photos 2019, ImageMagick (version 6.9.9-40) and python were used to create volume backscatter strength (Sv) profile images of the split-beam echo sounder data and extract navigation data from the Simrad .raw files. The processing flows and scripts used are summarized below.
1) Simrad .raw files were imported into ESP3 ('open file') by survey day. Using the 'layer list' tab, input files were evaluated for their time length and quality. Shorter files were concatenated ('merge selected layers') to produce continuous data sections approximately 1 to 4 hours long, and longer files were left as is. Files in which acquisition settings caused changes in sample rate mid-file, an issue that ESP3 recognizes but does not correct for, were generally left unconcatenated or included as the last file in a longer concatenated section (see logical consistency report for a list of files effected by this issue). Settings in the 'Display Options' tab determined several elements of the images produced; 'Data' was always set to 'Sv' (in dB re 1 m-1), X-Scale was always set to 300 seconds (for 5 minute annotation interval), the Y-Scale varied between 10 and 200 meters depending on the duration of the image, and default values were left in remaining fields. For each of the desired output sections, the zoom tool was used to restrict the image area above the deepest sea floor depth, and 'Export > Save Echogram' was used to create an output PNG file of the profile showing depth (meters, relative to instantaneous sea level) along the y-axis (left margin) and UTC time along the profile (labeled at 5-minute intervals), with a color bar scale for Sv (in dB re 1 m-1) along the right margin. Navigation was extracted from all of the Simrad .raw files using 'Export > Export Navigation GPS to .csv/.shp from raw files', specifying the all navigation option, and saved as CSV ASCII text.
2) Microsoft Photos 2019 was used to crop excess white background area from the output png profile images, then ImageMagick convert was used to reduce the images to 30% of their original size.
3) The python script pySQL_EK60nav_1m imported the navigation, year, day, and UTC time data from CSV files into a Spatialite (version 4.3.0) enabled SQLite (version 3.26.0) database, creating two tables containing point geometries. The first contained records for all of the input navigation coordinates, and the second maintained records for the first and last fixes in the files, and fixes nearest to even minutes. A 1-minute interval was chosen for convenient correlation to the 5-minute annotation interval provided along the bottom of the profile images. The resulting database columns for each table consist of Lon, Lat (WGS84 dd), LineName, Year_JD, JD_UTC (DDD:HH:MM:SS), SurveyID, VehicleID, and DeviceID. A third table was created to contain trackline geometries generated from all of the input navigation point geometries for each line (sorted by LineName and Time), and the line length in kilometers was calculated. The resulting database columns of the line geometry table consist of LineName, YearJD_init, JDUTC_init, YearJD_end, JDUTC_end, SurveyID, VehicleID, DeviceID, Length_km, and EK60_Image.
These process steps and all subsequent process steps were conducted by the same person - Wayne Baldwin.
Process_Date: 201909
Process_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey
Contact_Person: Wayne E. Baldwin
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd.
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Contact_Voice_Telephone: (508) 548-8700 x2226
Contact_Facsimile_Telephone: (508) 457-2310
Contact_Electronic_Mail_Address: wbaldwin@usgs.gov
Process_Step:
Process_Description:
PROCESS STEP 2:
The EK60 1-minute navigation points and trackline features for each field activity were added (Add Data) into ArcMap (version 10.7) from the SQLite database, then exported (Right click on database feature class >Data> Export Data) to the new Esri polyline shapefiles '2017-001-FA_EK60_NavPoints_1min.shp', '2017-002-FA_EK60_NavPoints_1min.shp', '2017-001-FA_EK60Tracklines.shp', and '2017-002-FA_EK60Tracklines.shp'. The ArcGIS process 'Merge' was used to combine the navigation point and trackline datasets into the single shapefiles '2017-001-FA_2017-002-FA_EK60_NavPoints_1min.shp' and '2017-001-FA_2017-002-FA_EK60Tracklines.shp'.
Process_Date: 201909
Process_Step:
Process_Description:
Added keywords section with USGS persistent identifier as theme keyword.
Process_Date: 20200806
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
