Mavic 3E RTK Pix 4D

[McCune Drone]

We did a flight, using the Mavic 3E with RTK and the DJI Base, post processed our GCP we shot in with our GeoMax Zenith 60, we used Pix4d. When we post processed we were having issue. We were having up to two feet in discrepancy in our elevations between the points and the data from Pix4d.
Also how do you post process so that the road come out like what you see in contours you can download from the internet.
Please dont say Lidar, we cant afford it.
Any help would be greatly apricated.

 

[jaja6009]

First Problem.

Was your drone receiving corrections?
If so what datum/coordinate system were your corrections in?

Was your DRTK setup on a known point and what vertical coordinate system was it using, ellipsoid, orthometric?

When you say GCP, you mean your control points were only used as GCPs and not check points? Make sure you choose the correct datum and coordinate system for your GCPs/Control Points/Check Points.

Then choose whatever output datum/coordinate system that meets your needs. My state demands State Plane, US Survey feet.

Your other problem could be if you used either all nadir images or nadir with altitude optimization or all oblique images. If you only used just nadir only, this will cause a vertical shift. If you used nadir with altitude optimization or all obliques or a mix of obliques and madir then disregard.


Second Problem.

Your contours look the way they do due to the extremely fine resolution of your DEM.
When I do contours I will take the point cloud, import it into Arc Pro then:
1. Import DEM
2. Create Boundary polygon
3. Fishnet Tool Lines – Use Polygons
4. Remove polygons
5. Selection, select point completely within Boundary
6. Create Feature Class from Above
7. Add Surface Tool to create elevations to points
8. Create TIN tool
9. Create contours from TIN