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Geospatial Video Monitoring of Benthic Habitats Using the Shallow-Water Positioning System (SWaPS) Diego Lirman and Greg DeAngelo Diego Lirman and Greg DeAngelo Rosenstiel School of Marine & Atmospheric Science University of Miami NOAA / National Geodetic Survey
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Shallow-Water Positioning System (SWaPS) SWaPS was developed by researchers from NOAA’s National Geodetic Survey Video-based technology used to establish the location of objects underwater Merges Visual and Position information Multiple platforms (shallow draft skiff, remotely operated, diver-operated) Used to survey seagrass, hardbottom, coral reef habitats
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BASE STATION GIMBALL ASSEMBLY GPS ANTENNA DIGITAL VIDEO CAMERA GLASS PORT RTK SHALLOW-DRAFT SKIFF
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SURVEY PLATFORMS. Shallow-draft skiff
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SURVEY PLATFORMS. Remotely Operated SWaPS
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SURVEY PLATFORMS. Diver-Operated SWaPS Dome Transducer Monitor Batteries Depth Sounder Digital Compass & Tilt Meter Camera G.P.S. Encoder G.P.S. Antenna Dome Transducer Monitor Batteries Depth Sounder Digital Compass & Tilt Meter Camera G.P.S. Encoder G.P.S. Antenna
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SWaPS. Precision and Accuracy The precision of SWaPS was tested by deploying numbered ceramic tiles (15 cm x 15 cm) @ 1 m of depth in Biscayne Bay, Florida The position the tiles was obtained from the video frames showing each tile The following day, the tiles were relocated using an RTK-GPS navigation system With the GPS unit as a guide, the boat was repositioned over each waypoint. If any portion of the tile could be seen on the video frame, the tile was counted as a hit SWaPS can provide sub-meter precision consistently in shallow coastal areas. 80% of tiles were relocated within the video frame using only the positions recorded during deployment For the tiles that were not relocated within the video screen, the mean distance to the center of the frame was 75 cm
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SWaPS. Precision and Accuracy The accuracy of SWaPS was tested by deploying tiles on a Florida reef (2.5 m of depth) and a swimming pool (1.5 m), and determining their position using the diver SWaPS The distance between tiles was calculated from GPS positions and compared to the same distances measured by divers in the field using tapes. Distances between tiles ranged from 2 m to 10 m. 125 117 138126 101 6767 15 9 11 3 12 4 14 6 5 2121 2323 16 3 16 9 1616 178 1097575 137 543 652 369 632 572565 407 444 405 317 337 404 411 467599 440 479 329 325 354 475 FIELD MAP SWaPS POSITIONS The mean deviation between diver and SWaPS measurements was 22 cm (min = 1 cm, max 50 cm). These deviations were < 10 cm in the pool
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Applications: 1)Benthic Monitoring: Assessment of Submerged Aquatic Vegetation in Shallow (< 1 m), Nearshore Habitats not Easily Accessible by other Survey Platforms 2)Damage Assessment: Impacts of Boat Propellers on Seagrass Communities and Ship Groundings on Coral Reefs in an Accurate, Cost-Effective Manner
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RICKENBACKER CSWY TURKEY POINT N = 249 Sites 20 - 30 M TRANSECTS RANDOM IMAGES FROM EACH SITE % COVER FOR EACH SPP/GROUP NEARSHORE BENTHIC HABITATS OF BISCAYNE BAY Data from all sites used to produce SAV abundance and distribution contours SAV abundance and distribution contours
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SWaPS SURVEYS IN THE VICINITY OF CANALS Mean % Cover Halodule wrightii Thalassia testudinum
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SWAPS can provide an ideal platform to assess damage and recovery patterns by: 1) Documenting the precise location of impacted resources (e.g., seagrass scars, ship groundings) 2) Quantifying the extent of damage accurately and remotely without causing additional disturbance to the resources and without the need to deploy specialized personnel 3) Providing an objective, permanent visual record of damage patterns that can be used to assess recovery over time DAMAGE AND RECOVERY PATTERNS Damages from boating activities are a major cause of disturbance to coral reef and seagrass communities worldwide
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SEAGRASS PROPELLER SCARS
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SHIP GROUNDINGS
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1)The ability to survey large areas rapidly without the need to deploy divers or specialized field personnel 2)The ability to return to precise locations with sub-meter accuracy over and over without the need to establish permanent markers 3)The ability to measure size and distance information underwater to provide valuable tools in restoration and damage assessment studies 4)Collection of a geocoded visual archive of the status of resources that can be easily accessed for future reference ADVANTAGES OF SWAPS
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ACNOWLEDGEMENTS Funding Sources NOAA’s National Geodetic Survey DOI’s NPS CESI Program NGS Gerry Mader NPS Sarah Bellmund Richard Curry NOAA JOE Serafy Joan Browder UM Jimmy Herlan Lexie Brown Rachel Clausing
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GRACIAS!!
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