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Desktop - Pix4DMapper Z axis inverted when using GCPs

Hello,

We are using a set of 390 geolocated images from DJI Phantom 4Pro covering 3Ha. 

There are five GCPs with ID, Northing, Easting, Elevation  data in meters (arbitrary coordinate system)

Using GCP Manager/Editor, each of the GCPs were associated with 3, 4 or 5 images. 

The problem is this:  

When processing with GCPs - the cameras all appear to be looking UPWARDS and the resulting cloud is inverted with +Z down 

However:

Processing without GCPs - the resulting cloud is oriented correctly and referenced to WGS84 UTM 10N as expected.

Why would adding arbitrary GCPs cause this inversion?

GCP file: 

1002,5440709.383,497996.837,0.552
1003,5440715.502,498052.966,0.311
1004,5440881.230,498054.215,0.312
1005,5441055.452,498032.473,0.958
1006,5441054.981,498127.123,0.390

Northing Values increase towards the North, Easting values increase towards the East

Thanks for any insight!

Donald Gibson

HighCee Aerial Robotics

Hello Don,

We are also in contact via support ticket where you have sent some screenshots. I could see that as soon as the GCPs are introduced, the project is rotated.

I give my answer here too as it can help other users experiencing the same issue.

I think that what is happening is that the GCPs are imported wrongly.
By looking at your GCPs, the first column contains the ID, the second the Y coordinate and the third the X coordinate.

Could it be that the import was wrong and the import order was x,y,z?

Thank you very much,