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Inverted ATPs and Orthomosaic


I am trying to process some imagery captured from a X4S (part of a Klau PPK system).  I imported the Klau-provided lab-calibrated camera parameters and imported the image post-processed positions .csv prior to Step one.  The images in WGS84 came in fine in the Map View (1st capture below).  I did not specify a geoid, so the image altitudes are heights above ellipsoid. 

When I ran the 1st Rapid Processing step, the automatic tie points and initial orthomosaic preview seem to be inverted.  Please see images below.  I even swapped the camera to the default one and got the same results. Quality Report link in below:!AshJwvSEGv7qi4wakNa8ScZ7_FuwMA

Map View - Note road on the east

Ray Cloud View…why are initial camera positions pointing down and the calibrated/adjusted cameras are pointing upward beneath ATPs?

When I review the Quality Report Ortho Mosaic preview, I see the road on the west side…like it is a mirror image. 


Any help will be greatly appreciated.


Hi Micahel,

I would say there is a scale problem as the area covered with the initial geolocation is larger than the area  covered after the adjustment:



Since you are using “All prior” as camera optimization, I would use “All” to let the software change the internal parameters.

I would also covert the PPK coordinates from WGS84 into your NAD83 system. Please have a look at this post: [Desktop] Horizontal grid corrections and transformations

Another thing that you could try is using “Geometrically verified matching”:


Please let me know how it goes after these recommendations. If it still fails, would it be possible to share the data?

Thank you very much.


Hi Daniel,


Thank you for your response.  I actually have found the problem and it was not a Pix4D issue.  It was related to the PPK image location.csv file I imported into Pix4D prior to Step 1.  This file was outputted after processing PPK data.  The issue centered on me not removing about 20 logged GNSS camera events for the beginning mission segment (with no SD card) prior to creating the image location.csv.  Once I removed these events in the PPK software, and re-exported only the final PPK camera events from the mission, it imported perfect into Pix4D.


Thanks for your feedback.

Good to see that it is working now.