Surveying Mountain area with Phantom 4 Pro and Pix4D Capture

PIX4Dcapture PIX4Dcapture Questions/Troubleshooting
1

Hello!

Any advise how to make survey Mountain area covered with forest? When I am on top of the mountain and set flying height to 50 m in Pix4D android App, it fly at this height, but DOES NOT FOLLOW the terrain, is it good for survey? Or do I need to adjust options so it will follow the terrain? the elevation is changing rapidly.

Also could you please tell me how to make 3D model of the mountain (standing at the bottom) fully? I mean also to include mountain SIDE details (if looking from drone perspective view, trees cover side of the mountain), do I need to set to manual mode and take photos of the side? If so, how to do it, what interval, height and camera angel?

Please have a loot at attached photos, where i demonstrate the example of “lost data” when i take photos only from above and try to make 3D model of the terrain. Here Mountain side view isnt visible to drone from above, because of the hovering trees above terrain.

 

Thanks!

2

Hi Lado, 

The goal for the image acquisition would be to minimize the variation of Ground Sampling Distance (GSD) throughout the project. 

You mention that the side of the mountain is not entirely visible when using nadir images. In that case, we would suggest to acquire oblique images of the area that have enough overlap with images taken from the top and that have a similar distance to the mountain side (to keep a similar GSD). 

As for the height variations, you could do several smaller missions that have overlap between each other, each at the same distance from the ground as described here: https://support.pix4d.com/hc/en-us/articles/204656209-Image-Acquisition-Plan-for-Terrain-with-Height-Variations 

For this you could use the Project List feature in Pix4Dcapture Android: https://support.pix4d.com/hc/en-us/articles/208820126–Android-How-to-use-the-Project-List

Note that there can be differences between two flights, but the maximum distance is twice the flight height for the same camera, otherwise it becomes difficult to find matches between images and to reconstruct the project, more here: https://support.pix4d.com/hc/en-us/articles/202558979-Can-Pix4Dmapper-process-Images-taken-at-different-Flight-Heights 

The flight plan for forest and dense vegetation can help too: https://support.pix4d.com/hc/en-us/articles/202557459-Step-1-Before-Starting-a-Project-1-Designing-the-Image-Acquisition-Plan-a-Selecting-the-Image-Acquisition-Plan-Type#label2 

Hope this helps!