First Orthomap made along with accuracy assessment

[jaja6009]

I finally got a chance to make my first map.
I made it a shootout where i tested:

Matrice 4 E
Phantom 4 RTK
Mavic 2 Enterprise Advanced with RTK module (I know the RTK module does not have Time Sync for the images)

I did not map by GSD, all drones flew at the same altitude @ 125 AGL.
5 Control Points were used as Check Points, so no Ground Control Points

Matrice 4
1 map made with all nadir images and one line of oblique Altitude Optimization
1 map made with all oblique in a classic double grid

Phantom 4 RTK
The mechanical shutter broke mid flight knocking this drone out of service

Mavic 2 Enterprise Advanced with RTK Module
1 map made with all nadir and one line of manually flown obliques since this drone does not support Altitude Optimization
1 map made with the 5 route oblique missions


Results
Matrice 4 E Nadir - 103 images


Matrice 4 E Oblique Double Grid - 296 images





Mavic 2 Enterprise Advanced Nadir - 114 images




Mavic 2 Enterprise Advanced Oblique and nadir - 320 images




There is room for improvement. The nadir map was very good and what I expected. With the Phantom 4 RTK though, when using oblique images the RMSE almost always got lower. Here with the Matrice 4 E and oblique only images, it went up and was actually disappointing.
I consistently get lower RSME with my Phantom 4 RTK.


Here is the results of mapping the area previously with the P4RTK.




I am still dialing in the images. I think they are a tad blurry. Next time I will address the focus issue by using autofocus once at altitude and then switching to manual focus/infinity. I used Shutter Priority, 1200 speed trying to keep the aperture between 4 and 5.

I will conduct more tests and see what happens. I think this is still a few firmwares away from being dialed in.


Here is a link to the maps online:

https://cloud.agisoft.com/shared/projects/f37b9302-b457-4c50-949d-f414ecd74d6e?position=-74.457671,39.357789,154.567667&orientation=360,-90,0

 

[jaja6009]

I got a chance to introduce the Matrice 4 to my beach mapping project.
The accuracy was very interesting, to say the least.

I use Agisoft Metashape Pro. I have a dedicated workflow that I use and it works great for the Phantom 4 RTK and Mavic 3 E.

When I used this workflow using Gradual Selection (Removing the worst points in terms of accuracy and error) I found that the Matrice had very bad accuracy.

When I changed the parameters for Gradual Selection I acheived really good results.

But the surpirse was that when using either Gradual Selection method, my results were not repeatable on other projects which surprises me. I will need more projects to see what is going on.

Any way, for my beach projects I cannot have the proper GCPs and Check Points on site due to people touching, moving or taking them. So I only use 1 GCP and 1 Check point. This will at least let me know after processing if Ihave any major issues. I will then take the point cloud and use Cloud Compare to check various static points to obtain the RMSE.

When using a new Gradual Selection process and also using the Camera Calibration from the metadata, I acheived an impressive RMSE for the Matrice.

I used both control points as Check Points and did not use one as a GCP and my results were:



I will now use Cloud Compare to assess other static points for a more spread out RMSE analysis.


All images were 60 degrees oblique and a double grid was flown. The sUAS flew at 200' AGL and I used Auto for the camera setting.
Auto setting works well in that it kept ISO at 100 to 410 (410 being a bit iffy), shutter speed at 1/500 to 1/2000 and aperture at 2.8 to 4.5.
I usually use Shutter Priority but have been testing out Auto with decent results. I would like the majority of images to have the aperture at 4.0 to 5.0.
Auto also will have the drone autofocus before the first picture and then switch to manual focus infinity.


I also ran the dataset in Pix 4D matic and mapper.

Pix4Dmatic




Pix4Dmapper