Desktop - Pix4DMapper Z axis inverted when using GCPs

PIX4Dmapper PIX4Dmapper Questions/Troubleshooting
1

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

2

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,