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Using Geospatial data to assess storm damage

williamtweldon

A storm came through West Lafayette, spawning a tornado and destroyed one of Purdue's Agricultural barns. We were able to take the class out to the debris field and gather data with two different platforms. One of the goals of this flight was to experiment with using Loc8 and geospatial video to determine the location of the debris in the path. Using these software packages to find debris, could assist communities in disaster recovery by decreasing the amount of time required to clean up after a disaster. A student team processed the debris field data in Pix4D to create an orthomosaic, and 3D mesh.

Figure 1: Orthomosaic

This gives us a rough idea of the size of the debris field, and the direction it is going. f we were to use this image to collect the debris we would run into a problem. The debris collectors would lose track of where they were in the field because the environment is very uniform. This might prevent them from collecting all of the debris on their first attempt, and subsequent flights may need to be performed. By using Loc8 this problem can be removed.

Figure 2: Loc8ed debris

Figure 3: Debris location

Figure 2 shows that Loc8 found a ton of false positives during it's search for the debris in this image. While this isn't perfect it isn't bad. The software still found the debris, and provided us with a GPS coordinate for everything in the image. If we were to send out debris collection teams we could provide them with a list of GPS coordinates for them to search, as long as the images were reviewed beforehand and appropriately flagged/archived (as suggested in Loc8's tutorial videos). The downside to this approach is that the GPS coordinate is for the entire image, so searching would still be necessary. This could be easily mitigated by providing the collection teams with the flagged images for referencing in the field.

The third method that I investigated for debris cleanup was using LineVision geospatial video.

Figure 4: Debris pattern in LineVision

Figure 5: Frame with desired debris

Figure 6: Debris coordinates

Using LineVision I found the same debris that can be seen in Figure 2. This software was able to provide the GPS coordinates of the object inside the image, as opposed to the GPS coordinates where the image was taken. This coordinate was provided after I identified the debris and manually marked it. In disaster cleanup this software could be used to provide cleanup teams with checklists for debris removal.

Each software package used for debris analysis is very capable, but for tracking debris it would seem that LineVision is the best. The capability to remove any sort of guessing from debris removal is very appealing, and could reduce cleanup times. Loc8 provided similar capabilities, but was not able to be as exact as LineVision in this situation. Where Loc8 shines is in situations where manual tagging is impossible or infeasible, and in this situation the debris was very easy to manually tag. Pix4D was not a good choice for locating the debris. While the orthomosaic does include the debris it does not provide much in the way of location information for removal. Where Pix4D was useful was in assessing the damage done to the barn that created the debris, figure 7.

Figure 7: Barn

The condition of the damaged barn surprised all of us. We collected data two days after the storm, and the barn had been completely torn down by then. Had the barn still been standing we would have been able to use Pix4D to assess the damage of the building, but instead we were able to assess the cleanup efforts.

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