Langlois, Lucas; McKenzie, Len J (2022): Seagrass meadows derived from field to spaceborne earth observation at Green Island (Wunyami), a reef habitat in the Cairns section of the Great Barrier Reef, November 2020 [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.946605
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Abstract:
Seagrass meadow extent and meadow-scape was mapped using two alternative approaches at Green Island, a reef clear water habitat, in the Cairns section of the Great Barrier Reef, in November 2020. Approach 1 included mapping seagrass meadow-scape (including patches and scars) using imagery captured during low spring tides with a DJI Mavic 2 Pro UAV at an altitude of 100 m (85% sidelap and frontlap) on the 25 November 2020. The orthomosaic of the captured images was created in PIX4D and the resolution was 2.45cm/pixel. Approach 2 used PlanetScope Dove imagery captured on 05 November 2020 coinciding as close as possible to the field-surveys from 25 to 27 November 2020, with 3.7 m x 3.7 m pixels (nadir viewing) acquired from the PlanetScope archive.
For Approach 1, spatially explicit seagrass maps were created, including seagrass cover, from the UAV nadir imagery using deep-learning techniques. The abundance classes used were: (1) absence of seagrass (0%), (2) low seagrass cover (1-15%), (3) medium seagrass cover (>15-50%), and (4) high seagrass cover (>50%). For Approach 2, we created spatially explicit seagrass maps from PlanetScope Dove imagery, and conducted the classification using a machine-learning model (Random Forest) coupled with a Boot-strapping process (100 iterations). The final model predictions were then gathered into separate rasters, based on Bootstrap Probability thresholds of 60% and 100%. The final rasters were cleaned using a majority filter algorithm, to eliminate stray pixel predictions using a moving window between 3 and 9 pixels depending on the size of the imagery.
Related to:
McKenzie, Len J; Langlois, Lucas; Roelfsema, Christiaan M (2022): Improving Approaches to Mapping Seagrass within the Great Barrier Reef: From Field to Spaceborne Earth Observation. Remote Sensing, 14(11), 2604, https://doi.org/10.3390/rs14112604
Coverage:
Latitude: -16.760000 * Longitude: 145.980000
Date/Time Start: 2020-11-05T00:00:00 * Date/Time End: 2020-11-27T00:00:00
Event(s):
Green-Island * Latitude: -16.760000 * Longitude: 145.980000 * Location: Great Barrier Reef, Australia
Parameter(s):
| # | Name | Short Name | Unit | Principal Investigator | Method/Device | Comment |
|---|---|---|---|---|---|---|
| 1 | DATE/TIME | Date/Time | McKenzie, Len J | Geocode | ||
| 2 | GIS file | GIS | McKenzie, Len J | |||
| 3 | Documentation file | DOCS | McKenzie, Len J |
License:
Creative Commons Attribution 4.0 International (CC-BY-4.0)
Status:
Curation Level: Basic curation (CurationLevelB)
Size:
6 data points