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NAVD 88 GCP's processed using EGM96


I recently completed a large corridor project involving several dozen RTK GCP’s all with NAVD88 elevations. I now realize that the project was run with the input coordinate system of the GCP’s as well as the output coordinate system for the project set to EGM96. Is my output in a consistent coordinate system, or will I need to rerun the project to get meaningful elevations? I am looking for a vertical accuracy of roughly 6 inches. I would ultimately like my coordinates in NAVD88, and am aware that to do this, Pix4D currently advises using an arbitrary coordinate system with NAVD88 inputs. This is an option, but I would like to avoid reprocessing my project if possible. 


Thank you in advance!

Hello Derek,

There is no need to process your project as the computation will tie the whole project to the GCPs.

Anyway, please check the altitude of the GCPs in the rayCloud where you can always see the initial and computed altitude to be sure.


Great to hear! Thank you very much. 

For future reference, what would the difference be if my input coordinate system of NAVD88 GCP’s as well as the output coordinate system for the project were set to Arbitrary?

Hi Derek,

The coordinate systems are written in the prj files of the outputs.

If you use arbitrary and you give any output to a client, they will not know what is the used system.