Researchers have developed a way to use satellite imagery data to create 3D images that can quickly detect changes in the Earth’s surface, new research says.
With this tool, you can quickly detect serious natural disasters that occur in remote parts of the globe and provide first responders with accurate information about the needs of the affected areas.
Operated by the satellite data company Planet, the Planetscope satellite constellation collects images of the entire globe weekly and possibly daily.On average, that Cubesat fleet, or Miniature satellite, There are about 1,700 images of everywhere on earth. The data they collect have been used to monitor the spread of wildfires, detect changes in crop health, and investigate areas of deforestation.
This kind of global coverage is unprecedented, said Rongjun Qin, co-author of the study and associate professor of civil engineering, environmental and geodetic engineering at Ohio State University.
“There are many significant benefits to satellites in that they cover the Earth very quickly,” said Hata, a core faculty member of the Translational Data Analytics Institute at Ohio State University. “We focus on informing the community about changes in our cities, forests and ecosystems.”
Studies published in the journal GIScience and remote sensingPlanetscope vast data set It can be used to create a 3D reconstruction or digital surface model of any area.
“Remote sensing can help estimate areas affected by natural disasters,” says Qin. “We were able to figure out how many people would be dispatched for rescue operations and observe the level of damage these events would actually cause.”
Before Remote sensingBased disaster investigations have been limited by the lack of available data and coverage and resolution, or the frequency with which images are collected or updated.
For example, many are familiar with Google Earth. This is a computer program that renders a 3D representation of the Earth using satellite images and aerial photographs. However, a popular program is one of the reasons why the Qin team wanted to create a model with much higher resolution or update rate.
“Some places on the site have very nice 3D reconstructions,” Qin said. “But there are many places where those images on Earth are distorted.”
A purely flat image overlaid on the globe will cause objects and locations on the map to appear out of scale, which can adversely affect the accuracy of the entire program.
However, taking into account different elevation levels and landscapes, Qin’s 3D reconstruction is accurate up to about 6 meters above the ground. When it comes to data mapping, he said, it’s similar to achieving “almost one pixel accuracy.”
And the Planetscope data Open access For educators, other scientists can use the same dataset that the study used to create their own simulations. According to Hata, in an area as large as the Ohio State University’s Columbus campus (1,600 acres), it takes less than an hour to convert satellite imagery into an accurate 3D reconstruction of the area.
However, to test their method, Hata’s team devised three different case studies, or experiments using thousands of Planetscope images collected between 2016 and 2021.
In one test case, satellite imagery was shown to be able to perform 3D reconstruction of urban and rural areas of Spain. A second test case showed that it was possible to detect 3D changes over time in urban areas and woodlands near Allentown, Pennsylvania.
To determine how good their model is in post-disaster assessment, one experiment investigated the glacier region of Chamori, India.
Last year, the area surrounding the area was hit by a catastrophic flood, killing hundreds of people and destroying two nearby power plants. Advances in satellite technology later revealed that floods were caused by rock and ice avalanches.
Their results showed that their model could not only reproduce what was modified. terrain It led to a disaster, but explains the amount of avalanche rocks and ice. “We have confirmed that we can use Planetscope’s digital elevation model to evaluate similar global mass changes. Natural disasters For an avalanche event, “said Hata.
Qin’s findings help us design better ways to take advantage of it. Hygiene As the number of data, especially the number of satellites and their various applications, grows.
“This is still in the incubation stage and requires engineering effort, but I think it will be a big problem for scientists interested in the industry and the fight against climate change,” he said.
Co-authors of the study include Debao Hung and Yang Tang of The Ohio State University.
Debao Huang et al, Evaluation of Planetary Mirror Images for 3D Reconstruction and Change Detection-Experimental Verification by Case Study, GIScience and remote sensing (2022). DOI: 10.1080 / 15481603.2022.2060595
Ohio State University
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Use of satellite data to support direct response to natural disasters
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