Vertical Coordinate System - Is output in GEOID of GCP?

PIX4Dmapper PIX4Dmapper Questions/Troubleshooting
1

Hello,

I am working on a project that uses GCPs in NAVD88 and GEOID model GEOID18. GEOID18 is not an option for Pix4Dmapper, and the quality report states it that the output is in GEOID EGM 96.
Is my data being transformed to EGM96 even though my GCPs are in GEOID18 since PIX4Dmapper doesn’t have the option I need? And is there a workaround to avoid this? I need my data to match the GCPs I’m using.

Thank you.

2

Hi Ramiro,
PIX4Dmapper will respect your GCPs and align the outputs accordingly. You can set your vertical coordinate system to Arbitrary so that the quality report does not state EGM96. Ultimately, the GCPs will determine the elevations. Hope this helps.

1 Like
3

Thank you! I wanted to confirm since the quality report still states EGM96 and the client does not want the quality report to show a GEOID that is not accurate.

4

Since GEOID18 isn’t an option for the GCP coordinate system, does EMG96 overrule the GEOID my GCPs are in?

5

Hi @Ramiro_Massa

As Mike stated if GCPs are used, by default, Pix4Dmapper outputs the same height (ellipsoidal or geoid) as the GCPs.

You can have a look at this article: When to use the Geoid Height Above the Ellipsoid Function?

By setting the vertical coordinate system to Arbitrary, it will not show EGM96 in the quality report. :+1:

An even better solution would be using PIX4Dmatic which already comes with |more options for supported geoids: How to use vertical coordinate systems and geoids - PIX4Dmatic. If you are interested, you can try a 15-day free trial by clicking here: Download PIX4Dmatic photogrammetry software

Sincerely,
Rosana (she/her)