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Vertical Coordinate System not found

Hi there,
I’m working on a project in Northern Alaska, XY coordinates are in NAD83(2011) UTM6N,
my vertical coordinate system was taken in NAVD88 msl via Geoid 12B.

This is not an option when importing GCPs or setting image locations. I tried running “Arbitrary” as per one of the solutions I found in another forum, and it resulted in this warning on my report:

I’m wondering if anyone can help troubleshoot this.

Thanks!

Hi Jaylene,

Welcome to the Pix4D Community. :slightly_smiling_face:

You are right. PIX4Dmapper does not support local geoids.

You can use Arbitrary or, if the area is small, you can even select ellipsoidal height and assign an offset.

(However, if you want to use the Geoid 12B, you can use PIX4Dmatic which supports it)

Regarding the No 3D GCP error, it looks like the Ground Control Points (GCPs) were not marked properly.
Would it be possible for you to share the entire quality report in the community? If you don’t want to share this information with other users, you can open a support ticket with us here:

https://support.pix4d.com/hc/en-us/requests/new?

Cheers

Thanks for the response. What would a small area be? and how would i calculate an offset? Thanks!

And I realized I needed to optimize after setting the GCPs but I am getting an RMSE of 0.292

Hi Jaylene,

The limit of the area really depends on how the local geoid undulations are in your region. Here you have to do an assumption: Is the variance of the geoid-ellipsoid offset so small in your area that you can assume to be a constant over your area of interest?
For example, if I’m mapping just a couple of square meters, I can assume that the difference between the geoid and the ellipsoid is constant over the area of interest. If I’m mapping on a larger scale (several square km) the difference can change.
To calculate the offset you need to know the difference between the ellipsoid and the Geoid 12B in your area.