US Feet or International Feet

PIX4Dmapper PIX4Dmapper Questions/Troubleshooting
1

Hello, 

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? 

Thanks!

 

Mike

2

Hi Michael.

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

3

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.

Thanks,

 

Mike

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5

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?

Thanks.

6

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!

Gary

7

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?    

Thanks.

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https://support.pix4d.com/hc/en-us/articles/202560439-How-to-get-the-Pix4Dmapper-Measurements-in-feet 

1 Like
9

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:

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Yes ! International.

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

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11

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?

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You might find this interesting,

https://community.pix4d.com/t/7365-Avoiding-problems-with-incorrect-Orthomosaic-elevations-using-feet-instead-of-meters-using-State-Plane-or-seeing-a-Black-pane-with-red-dots-during-processing 

My ref:

https://community.pix4d.com/t/6119-coordinate-system- 

 

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

 

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13

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

14

Hi Mike,

Thank you Gary for replying.

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

Regards, 

1 Like
15

Hi Gary,
I am in Califorina Zone 5 (Los Angeles Area). With so many EPSG options and GIS (QGIS) having limited options of EPSG (state plane) to choose. I think I am using the correct EPSG for my base map which was collected using NAD83 (2011) NAVD88 Epoch 2017.50 Geoid GSR80. Currently, my base map is in GIS using EPSG 2229. Any input to help me understand if I aligned?

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Hi gabriel,
EPSG 2229 is NAD83 / California zone 5 (ftUS). It is likely that you need your datum on NAD83 (2011), which is the latest version of NAD83. You might need to use EPSG:6424. This will be NAD83 (2011)/ California zone 5 (ftUS).

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Mike, I did some test and I love what I see. I am using the NAD83( 2011) (6318) for ViDOC collection, and viewing the data in GIS using the NAD83 EPSG : 2229 and the data is seamless. I have a LiDAR basemap in GIS and the new terrestrial data fits perfectly. Thank you. With California, we have many options, and I needed to be sure I selected the correct datum. Thank you for your time. The ViDOC with Iphone is amazing.