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Two Flights of same area giving two elevations

We flew the same site, once east-west and again north-south. the two patterns gave drastically different elevations. Two two plans of elevation converge on the east end of the site and diverge by about 25’ on the west end.
when I add the GCP points, a ~4’ error shows up in the results and portions of the match points are still on the wrong plan. Has anyone encountered this?

Hi, You will need to process the 2 flights as separate projects due to inaccuracy of the altitude values in teh image EXIF and then merge with GCPs or MTPs. Another quick workaround that might be interesting is to manually change the altitude of the images directly in Pix4D software by following this procedure (since you have GCPs)

  • In the Image Properties Editor right-click in the Altitude column. This will allow you to change all the values at once with one click.
  • Enter the “corrected” altitude.
  • Run Step 1.

As a side note, following the above workflow will change all the z-values to the same value. Some precision might be lost but you should still be able to process the project and refine the final position of the project using the GCPs without facing difficulties.

Thanks, cant wait to try changing elevation manually