Drone photogrammetry is a process of capturing aerial images of the Earth's surface using a small unmanned aerial vehicle (UAV) equipped with a camera. With the help of photogrammetry software, these images are then stitched together to create a 3D model or map of the area. GSD and image overlap are two crucial factors that determine the accuracy and quality of the resulting map.
GSD refers to the distance on the ground that is represented by one pixel in the image. In other words, it is the measure of the spatial resolution of the image. The smaller the GSD, the higher the resolution and the more detailed the map will be. However, a smaller GSD also means that more images need to be captured to cover the same area, which can increase the processing time and the cost of the project.
Image overlap, on the other hand, refers to the amount of overlap between adjacent images. The higher the overlap, the easier it is for the software to stitch the images together accurately and to create a seamless map. However, a higher overlap also means that more images need to be captured, which can again increase the processing time and the cost of the project.
So, what is the relationship between GSD and image overlap in drone photogrammetry? The answer is that they are interdependent. A higher GSD requires a higher overlap between images to create an accurate map, while a smaller GSD requires a lower overlap.
For example, if the GSD is 1 cm/pixel, the recommended overlap is around 80%. However, if the GSD is reduced to 0.5 cm/pixel, the overlap can be reduced to around 60%. This is because a smaller GSD means that more details are captured in each image, which makes it easier for the software to stitch them together accurately even with a lower overlap.
GSD and image overlap are both important factors in drone photogrammetry. They are interdependent and should be carefully considered when planning a project. By finding the right balance between the two, you can create a high-quality, accurate map while keeping the costs and processing time under control.
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