If the team did get it right, the ground control points would often be swallowed by the lava they were trying to measure. “In order to lay useful ground control points, we had to predict which way the lava was going to go - which sometimes worked and sometimes didn’t,” explains Stephenson. However, the team found they couldn’t always rely on them. Ground control points are one of the best tools to ensure a high quality reconstruction. Reconstruction of the lava flow approaching the PGV powerplant. “A normal flight would only take ten to twenty minutes, and in the downtime we would move to the next location and process the data on a gaming laptop in the field.” “We’d fly every single day,” says Stephenson. Pix4Dmapper photogrammetry software, ESRI ArcMapġ5 to 20 minutes with rapid processing mode Project detailsĭJI Matrice 200, Inspire 1, and Inspire 2 drones DJI Zenmuse XT and XT2 thermal cameras DJI Zenmuse X5S and X4 visible cameras Trimble R10 and Trimble R8 GNSS Systems It also sat directly in the path of the lava, which was flowing in a straight line, directly towards the powerplant.Īs PGV employees shut down equipment and shifted the stock highly-flammable pentane to a safe location, the UH Hilo team had drones in the air. The Puna Geothermal Venture, or PGV, generated 25% of Hawaii’s power. Mapping vital infrastructure threatened by disaster Images which contain large amounts of black, for example, photos taken at night, or photos of cooled lava, are difficult for the software to reconstruct, while the heat signatures show up clearly.ĭr Perroy on drone mapping the volcanic activity | Video courtesy of UH Hilo To create accurate maps and models from images, Pix4D mapping software relies on finding commonalities between images - the same point in more than one picture. As well as meeting the legal FAA requirements, this also made the drones visible to the team.Īs well as being safer, the team found that using thermal images their results were more accurate. Lights were attached to the fleet of DJI Inspire drones making them visible at night for three nautical miles. The higher altitude also meant that fewer images were needed to cover the same area, allowing teams to capture data faster. This was well above the matter shooting out from the Kilauea volcano fissures. The UH Hilo team received special permission from the FAA to fly at night and higher than usual - 305 meters (1,000 feet) instead of the typical 122 meters (400 feet). Thermal cameras allowed the team to fly at night and through dense smoke “Every night or so we would go back, and the road would be hotter and hotter.” One key section of highway was monitored closely: “If they had to close this one road, it would have made the evacuation area much, much larger,” explained Stephenson. With a thermal camera, heat signatures from lava seeping just below the earth can be detected, providing insights of future activity.ĭr Perroy and his UH Hilo Spatial Data analysis & Visualization (SDAV) research lab were tasked with mapping the lava fissures in relation to infrastructure, roads and houses around the rural community of Leilani Estates, in the Lower East Rift Zone. Lava erupting from a fissure can reach 1,200 degrees celsius. “One thing we have now that we didn’t have in 2014 was a thermal radiometric camera that helps us map more accurately at night and enables us to capture large heat signatures,” says Stephenson. As a graduate student at the University of Hawaii, Stephenson collected data on a 2014 eruption. It wasn’t Stephenson’s first visit to the island - or his first time mapping lava flows. Stephenson worked closely with Dr Perroy’s UH Hilo team, assisting the USGS and Hawaii County Civil Defense. As the eruption entered its second month, Frontier Precision’s Nathan Stephenson, an applied geospatial engineer based in the company’s Denver office, flew out to support UH Hilo’s aerial mapping component of this effort. Ready to launch: team members prepare a DJI Inspire 2 drone with RGB camera | Photo by Tracey NiimiĪ disaster affecting so many people and so much infrastructure requires a diverse team and involved agencies and institutions at the Federal, State, and local levels.
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