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US Feet or International Feet


When you select “Feet” as the units in Pix4D, is that International Feet or US Survey Feet?  When you select a published coordinate system (like CA State Plane), is that US feet? 




Hi Michael.

Are you selecting the output coordinate system from the drop down menu in the advance mode?  

Hi Gary,

I’m referring to the initial selection during project set up.  It would also be nice to know how Pix4D handles the difference between US Foot and International Foot when it creates the processing deliverables like point cloud and ortho mosaics, etc.






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Thanks very helpful.  I see “USFT” for certain ones.  This solves if I use a “published” coordinate system. 

However, what if you select “feet” during project set up in an “arbitrary” system?  Is it US Feet or International Feet?


If you are using a DJI product to collect data without control, then input is arbitrary. If you do have control for input then define that system as well as the output system as required.

Hope this helps!


Hi Gary,

We have a Matrice 200 with a Klau PPK kit.  We use a Trimble RTK GNSS to establish GCPs and check points in the field and then use the Klau-proprietary software to post-process the drone imagery (prior) to the Pix4D processing steps.  I was told at a recent Pix4D training course (UAV Expo in LV) to use an “arbitrary” coordinate system for my situation (PPK and GCPs) for best Pix4D processing results. 

Circling back to my first question above.  When I set up a Pix4D project and specify an “arbitrary” coordinate system, I have to set up the project units.  There are only “Feet” and “Meters” in the drop down to select.  My question at this step is, does “Feet” mean International Feet or US Survey Feet?    


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Thanks…I get that there is a US Foot to International foot distinction for the published coordinate system options.  What about for Arbitrary systems?  What does “ft” refer to?  Please see below:

Yes ! International.

Pix 4D could do better in the specification but in their description (ft) is international.

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Thank you Gary.  Where did you find that “ft” is International for Arbitrary Coordinate Systems?


Pix4D support:

Can you please confirm this is the case?

You might find this interesting, 

My ref: 


And absolutely confirm Pix4D, this isn’t the first time for this question.


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Thank you Gary.  Most helpful.  Have a nice day.

Hi Mike,

Thank you Gary for replying.

When it is not precise " ftUS" for US feet, international feet is used (" ft").