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Hi,

I have done my initial process in desktop. After that I had picked the GCP Points and generated the Quality Report with RMS error 0.003 m.

Here I have attached the quality report of my project

http://www.fileconvoy.com/dfl.php?id=g3c1f22d7024f48291000107492c625e1d4d93cefb4

After that I had uploaded my project to pix4d cloud. The quality report of the cloud process of same project shows RMS error 1.816m

Here I had attached the quality report

http://www.fileconvoy.com/dfl.php?id=g15367a647a043a361000107493c739472be5e78ff7

Please look it out and give me a solution as soon as possible.

Hello!

This is a known issue found in corridor projects, which our developers are still investigating. 
See the illustration of the drift below.

The difference in results is not due to the platform on which you processed the project (Desktop/Cloud), but to the workflow you used to incorporate the ground control points (GCPs):

  • If incorporated  before  step 1, GCPs are only taken into account at the very end of step 1 which prevents them from applying stronger constraints than the image geotags (if there are any). As a consequence, they are not too strongly weighted and the project is not completely fitted to their position. 
  • On the contrary, during the reoptimization, GCPs apply a stronger constraint on the georeferencing of the project and the project is fitted to the GCP positions. In this case, there is no shift between initial and computed GCP positions.

When processing locally, there was no shift in the position of the GCPs in the Desktop project, because you added the GCPs  after  running step 1 then reoptimized. In the case of the Cloud instead, there was a shift between initial and computed GCP positions since, after adding GCPs and uploading to the Cloud, step 1 started again incorporating GCPs from the beginning (processing always starts from the beginning on Pix4D Cloud).

For corridor projects, I recommend you do the following:

  • Process the projects entirely on the Desktop.
  • Process the project partly on the Cloud following these instructions:
  1. Process step 1 on the Desktop
  2. Add GCPs on the Desktop
  3. Reoptimize on the Desktop
  4. Upload to the Cloud, where step 1 will be processed again.

In this Case, I had partially processed the project on the cloud. I had done Step 1, GCP marking and reoptimize in desktop. After checking of quality report i have uploaded the project on cloud.

 

Hey,

thank you for getting back to me. It made me realize that I had written something wrong. The following

  • "Process the project partly on the Cloud following these instructions:
  1. Process step 1 on the Desktop
  2. Add GCPs on the Desktop
  3. Reoptimize on the Desktop
    4. Upload to the Cloud, where step 1 will be processed again."

will cause you to have the shift in the project on the cloud, because processing always starts from scratch on the cloud, so whatever was done on the desktop is not used on the cloud when a project is uploaded. The only things that are uploaded are the .p4d file (with image marks) and the images, then the processing starts again.

As I mentioned, this issue is specific to linear projects and our developers are looking into it. In the meantime, you need to process this project on the desktop and upload single results if you need to share them.

Best,

Alice