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Altitude correction ?

Hi,

The altitude computed from the geotagged photos (nadir + free flight) is about 20 meters above the actual altitude (compared with actual sea level inside the project).

Is it possible to use MTPs to correct this altitude just by renaming MTPs into GCPs with corrected Z level?

Thank you in advance for your reply.

 

Dominique

 

Hello Dominique,

You can process with ground control points (GCPs) in order to fix these uncertainties.
About using GCPs: https://support.pix4d.com/hc/en-us/articles/202558699

If you do have GCPs, you could get for instance 5 points from a Web Map Service server over your area:

https://support.pix4d.com/hc/en-us/articles/202560149 

Since there is a vertical shift in both sub-projects, we would suggest to choose characteristics points for these GCPs that are in both (not only in the biggest one). 

Best Regards,