Geographic Information Systems
Geographic Information Systems (GIS) involve using maps, cartography, satellites, and drones to collect and explore spatial data. GIS are being used in this project to investigate the substrates of the coral reefs of Vavanga. This involves the use of drones and underwater camera systems to pinpoint different reef ecosystems and put the data into maps. We can then visit the sites again in future years to monitor any potential changes in reef health.
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Using GIS has revolutionised the way we can survey and monitor these reefs. Typically, transects would be used by a single diver to collect this data manually. However, by incorporating the use of a drone and underwater cameras, a far greater quantity of more accurate data can be collected. This is especially useful when you only have a limited time in the field with a vast expanse of area to cover.
Step One
First, we survey. Simultaneous surveys were conducted over various areas of the reef in the Solomon Islands. Underwater video was captured from multiple angles attached to the Scooter, while UAV video captured both the Scooter position and surrounding context.
Step Two
Then, the video processing, colour correction, and geospatial post-processing steps begin. UAV Full Motion Video metadata is generated, allowing Scooter video frames to be accurately located.
Step Three
After that, the classification can begin. GoPro video frames are analysed to record substrate composition and abundance. Multiple samples per frame are recorded to remove variation due to camera view angle.
Step Four
The final step is the analysis. Spatial substrate classifications will allow for detailed mapping and interpolation along transect areas. Samples also provide ground truth data for wider remote sensing classification of the wider reef area from UAV data or satellite imagery.