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Identification

Field Value

Title

NESP Biodiversity Hub Hunter Marine Park Towed Video Imagery

Alternative title(s)

NESP Biodiversity Hub D3 Project: still imagery of the seabed in the Hunter Marine Park

Abstract

Raw downward facing still imagery of the seabed for Hunter Marine Park acquired using NSW Department of Planning Industry and Environment towed video system aboard RV Bombora for the National Environmental Science Program (NESP Biodiversity Hub). Fieldwork was funded, both cash and in-kind, by NSW DPIE and NESP in Year 5 (2019) of the program for 8-10 days of towed video over areas surveyed earlier in the program using a multi-beam echosounder (MBES) in 2015-16 and 2018-19 (NSW DPIE). A report titled 'Mapping and characterising the rocky reef habitat, fish and sessile invertebrate assemblages of the Hunter Marine Park' is available on the NESP website. Sites were randomly selected across mapped areas of the park's inner shelf, >3NM offshore of Seal Rocks, Broughton Island and Outer Gibber and covering depths of ~25-110m. Georeferenced (XYZ)and time-stamped (UTC) still imagery is accessible via DPIE Information Asset Register (IAR) and NSW Sharing and Enabling Environmental Data (SEED) website and linked to the online annotation platform Squidle+.

Resource locator

Data Quality Statement

Name: Data Quality Statement

Protocol: WWW:DOWNLOAD-1.0-http--download

Description:

Data quality statement for NESP Biodiversity Hub Hunter Marine Park Towed Video Imagery

Function: download

Unique resource identifier

Code

c16ffe39-fb1d-4ace-8a6f-efa73a4939a6

Presentation form

Image digital

Edition

1

Dataset language

English

Metadata standard

Name

ISO 19115

Edition

2016

Dataset URI

https://datasets.seed.nsw.gov.au/dataset/c16ffe39-fb1d-4ace-8a6f-efa73a4939a6

Purpose

baseline for monitoring

Status

On going

Spatial representation type

video

Spatial reference system

Code identifying the spatial reference system

4283

Spatial resolution

1 m

Additional information source

Data were collected on 7-9 separate dates during the time period to acquire imagery once from each for the randomly selected locations identified at the start of the survey.

Classification of spatial data and services

Field Value

Topic category

Keywords

Field Value

Keyword set

keyword value

MARINE-Biology

MARINE-Coasts

MARINE-Reefs

PHOTOGRAPHY-AND-IMAGERY-Remote-Sensing

Originating controlled vocabulary

Title

ANZLIC Search Words

Reference date

2008-05-16

Geographic location

West bounding longitude

152.352905

East bounding longitude

152.653656

North bounding latitude

-32.619714

South bounding latitude

-32.428658

NSW Place Name

Port Stephens Great Lakes Worimi

Vertical extent information

Minimum value

-100

Maximum value

2228

Coordinate reference system

Authority code

urn:ogc:def:cs:EPSG::

Code identifying the coordinate reference system

5711

Temporal extent

Begin position

2019-10-20

End position

N/A

Dataset reference date

Resource maintenance

Maintenance and update frequency

Unknown

Contact info

Contact position

Data Broker

Organisation name

Department of Planning and Environment

Full postal address

data.broker@environment.nsw.gov.au

Telephone number

131555

Email address

data.broker@environment.nsw.gov.au

Responsible party role

pointOfContact

Quality and validity

Field Value

Lineage

Video surveying was undertaken following the recommendations detailed in 'Field Manuals for Marine Sampling to Monitor Australian Waters' ( https://www.nespmarine.edu.au/field-manuals-marine-sampling-monitor-australian-waters). Details of the NSW DPIE towed video system and equipment are provided in 'SeaBed NSW: Standard Operating Procedures of multibeam surveying' (https://www.environment.nsw.gov.au/-/media/OEH/Corporate-Site/Documents/Research/Our-science-and-research/seabed-nsw-standard-operating-procedures-multibeam-surveying-190101.pdf). XYZ positional accuracy of the still imagery is better than XY (3 degrees of slant range [eg. 2.6m radius @ 100m]; <1m POS MV GPS G2 and POS to USBL offset) and Z (~0.2m based on USBL and tow-fish camera P-sensor with 0.54m offset). Imagery was obtained during the period 21 October 2019 – 31 October 2020 using a DSLR still camera (Towed Digital Stills - TDS) and forward looking live-feed (fibre) video (Towed Digital Video - TDV). TDS were captured at 2s intervals along 80-90 x 200m transects and characteristically ~1m from the seabed with dual green lasers (spaced 100mm) for measuring seabed distance (horizontal). TDS were re-labelled using NSW DPIE naming convention (NSWDPIE_TDS_NESP_Hunter_Location_Site_transectnumber_Dateyyyymmdd_TimeUTChhmmss). Image (JPG) time-stamping in UTC extracted from associated EXIF (Exchangeable Image File Format) metadata; Transect metadata file (CSV) for each transect contains the following columns: 1) Filename (as above); 2) Timestamp yyyy-mm-dd hh:mm:ss in UTC; 3) Latitude_TDS (Y GPS coordinate of TDS from USBL); 4) Longitude_TDS (X GPS coordinate of TDS from USBL); 5) Depth_TDS (Z stills camera depth in metres = derived from Pressure-sensor on TDV + physical offset TDS to TDV Pressure-sensor (0.54m); 6) Latitude_Ship (vessel Y coordinate); 6) Longitude_Ship (vessel X coordinate); 7) Sounder_Ship (raw vessel depth sounder output in metres); 8) COG_Ship (vessel heading in degrees); 9) SOG_Ship (vessel speed over ground in knots); 10-12) Roll_SHIP, Pitch_SHIP, Yaw_SHIP of Ship; 13) Depth_USBL (Z offset calculated from USBL transponder to transceiver using slant range); 14) Bearing_USBL (direction from vessel to USBL in degrees); 15) Flag (Numerical data flag of range 1 – 3 indicating source of positional data, method outlined in ‘Absolute External Positional Accuracy’, NaN = True fish position). Image and image metadata records (generated in csv format) were uploaded to NSW SEED Amazon Web Service for access and annotation in Squidle+.

Constraints related to access and use

Field Value

Limitations on public access

Data Quality

Field Value

Scope

dataset

DQ Completeness Commission

Effective date

2020-07-16

Explanation

Water column imagery has been edited out of the dataset provided here but available upon request.

DQ Completeness Omission

Effective date

2020-07-16

Explanation

Where drop-outs of GPS positioning of the tow fish occurred, an interpolated value was calculated as described in the Lineage statement above. Forward looking video and recorded tow-fish parameters (i.e. roll/pitch/heave) are also available but not provided with this digital still dataset.

DQ Conceptual Consistency

Effective date

2020-05-18

Explanation

As the imagery is acquired using a moving platform some images may or may not capture part of the same section of seabed in subsequent images. Survey speed of ~1kt (0.51m/s); image capture rate 1 image every 2 seconds; and approximate area of seabed captured in each image (0.5 - 2m2); 2 laser pointers denote a horizontal distance of 10cm where visible. nb: tow-fish roll, pitch and heave values are recorded by the video camera and saved within the video data file.

DQ Absolute External Positional Accuracy

Effective date

2020-05-18

Explanation

XY position of fish is determined by relative position of USBL transponder (fish) to transceiver (vessel). GPS position is G2 quality (<0.4-0.5m XYZ in realtime equiv. RTK) and is relative to the vessels Centre of Mass (reference frame 0:0:0) with a 2.4m forward offset (X = -1.5) from transceiver to COM entered in the USBL software (Y = 0). USBL heading offset is checked following each installation (nominally 23 degrees from centreline) and USBL (Tracklink, USA) precision is 3 degrees of slant range value. Original still image time-stamping is synched with computer UTC (<1s) but image naming convention utilises USBL/Video text feed based on POS MV time ss:mm:hh dd:mm:yyyy (UTC) output. The Tracklink USBL system suffers from drop outs (noise, power) for fish positioning and so when dropouts occurred the following protocol was followed when processing and interpolating positioning data: 1. Extract raw USBL data and partition into transects: interpolate (running average) where gaps are <10s: marked as FLAG 1 in the metadata file; 2. Extract GPS and Fish position (and other data) aligned with timestamps for each image (image to USBL time offset <1s); 3. Import ship and fish positions into Arc, then identify outlier points using 4m radius filter for successive UBSL fish position fixes; delete values and interpolate (running average) where gap is <10s; mark as FLAG 1 in metadata file. 4. Determine a median and SD of layback for true fish fixes and generate new fish position values over periods of 10s and as calculation of the new fish position relies on the last fish position there is likely to be an increase in positional error for the assumed fish-position over time. To rectify this, we applied an incremental (linear) offset/adjustment to ensure that the end of the ‘drop-out’ period aligned with next available USBL fish position in the sequence (i.e. when USBL positioning returned); marked as FLAG 3.

DQ Non Quantitative Attribute Correctness

Effective date

2020-07-16

Explanation

No non-quantitative attributes are provided here

Responsible organisations

Field Value

Responsible party

Contact position

Data Broker

Organisation name

Department of Planning and Environment

Full postal address

data.broker@environment.nsw.gov.au

Telephone number

131555

Email address

data.broker@environment.nsw.gov.au

Responsible party role

pointOfContact

Metadata on metadata

Field Value

Metadata point of contact

Contact position

Data Broker

Organisation name

Department of Planning and Environment

Full postal address

data.broker@environment.nsw.gov.au

Telephone number

131555

Email address

data.broker@environment.nsw.gov.au

Responsible party role

pointOfContact

Metadata date

2022-06-02T00:50:01.022591

Metadata language