GIS is a computer software program that stores and displays images on earth’s surface captured by the user. This program interprets and analysis the data to understand relationships, patterns and trends too create 2D and 3D coherent images. Aerial images are usually rounded, so that maximum surface area can be covered in the image. This curvature can be seen in the photo we took above a boat ramp that is prone to tidal flooding. GIS can take this curvature and manipulate the photos, so the curvature is not an issue. GIS is a very advanced program, but McLeod informed us that manually added set points in the photos, we can have a more accurate coherent image. Anything can be used to physically mark these points. We used cones and paper squares to mark the points. The GPS on the quadcopter is not accurate, so McLeod uses a GPS to mark each physical point. This GPS is accurate within 2-cm left and right and 5-cm in height. This is then recorded by hand by the user. The benefit in using these points is that if the software fails to combine the images, or there are missing points, the user can manually enter the GPS points into GIS to fix the problem. As this software advances, the less necessary it will be to physically mark these points, but it is a nice back up to have encase something goes wrong in the program.
Boat Ramp Tidal Flooding
We reviewed the 24 aerial photos we took at one of the areas in downtown Norfolk that is prone to tidal flooding and we found flaws when McLeod went to put them together in the GIS software. The GPS in the quadcopter’s accuracy was off by a couple of decimal points this caused the photos to be grouped into 4 main way points instead of 24 individual way points. This can be seen in the photo, the way points are the blue squares and the yellow line is the flight path the software generated. The software was unable to put these photos together because of the photos overlapping. Another issue we ran into was not knowing the altitude of the quadcopter. The reading we received was hovering about 15-ft. when the quadcopter was hovering at 50-ft. This could be fixed in the future by attaching a sensor to the quadcopter that records altitude.
McLeod informed us on key features future teams need to include to get more accurate aerial photos.
- Automated flight path.
- Automated photo capture.
- Separate GPS with more accuracy than the on included on the quadcopter.
- Infrared camera for Water vs. Land detection
- Sensor for altitude detection.
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