Aerial survey tips (with a fixed-wing UAV)
Modified on: Wed, 3 Jun, 2020 at 6:27 PM
- Do not set side overlap less then 60% and forward overlap less then 80% to get good quality results.
- Do not be afraid to capture more photos then required, more than required is better than not enough, later on excessive images can be disabled.
- Do not set too slow shutter speed, otherwise blur can occur due to camera movement.
- Do not avoid to use GCP to improve results accuracy.
- Do not perform aerial survey of the same area for the whole day. Lighting conditions changes during the day and you may get photos of the same territory with different lighting (for example long shadows from the same structures pointing in completely different directions and having different shapes), so Metashape might fail to find common points on the overlapping photos.
- To achieve better overlap, we can recommend cross-to-cross routes, as shown in the image below.
- Do not perform aerial survey of forest areas lower than 300 meters above ground. Trees move due the wind and when capturing from a low altitude the Metashape may fail to find common points on photos.
- Do not perform aerial survey of forest areas in the leafless season. Trees without leafs have a lot of thin structures (tree branches) so Metashape will be hard to find a common points on photos and the trees would be poorly reconstructed.
- Do not avoid to perform two cross flights to get double overlap when performing aerial survey of urban areas and capture different walls of the buildings.
- Do not capture structures built of shiny and reflective materials in sunny weather.
- In case you need to reconstruct detailed 3D model, do not use drones with only nadir cameras, use drones with multi-camera system (nadir + oblique cameras) instead or combine single-camera flights with different oblique camera orientation. Such approach would help to get proper model and texture reconstruction of near-vertical surfaces (e.g. building walls).
|Nadir cameras||Oblique cameras|
- Do not capture photos with only water presented on it, capture photos with land/water presented in 50/50 ratio.
- Do not avoid to perform double or triple aerial survey of one area from different altitude to get good results at waterbodies areas reconstruction
- Do not capture water bodies in sunny weather - reflections would affect the reconstructions.
- Do not plan flight without proper elevation model considered.
- Do not perform aerial survey of mountain areas lower than 100 meters above ground.
- Do not avoid to perform double or triple aerial survey of one mountain area from different altitude to get good results of slope reconstruction.
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