GCPs to my project

When adding GCPs to my project, do I NEED to convert to a text file?

The GCP file format needs to be a .csv or .txt file. For more information, please go to the link below.

Kind regards,

Thank you for the help.

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I have a problem with getting the recognized PRJ file for my Pix4D Cloud on a project in a local coordinate system. I am in South Africa, may someone help recommend the coordinate system i can use. I have the GCPs in local coordinates and I could easily find them on the images but I can’t get that far; I’m asked so select a recognized coordinate system or upload a prj file.

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Welcome to the Pix4D Community.
Make sure you follow the descriptions found here:


I am attempting to use GCP targets but as SCALE NOT GPS coordinates, is that possible on Pix4D? I was looking at New Scale Constraint as an option but with that method, you cannot have more than one scale constraint.

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Hi Fia,

Could you please elaborate on what you are trying to do? Are you trying to apply an arbitrary coordinate system?
Let me now if Site Calibration is the feature you are looking for.


Thank you for your reply. I checked out the article you attached. Seems like you require GCPs before site calibration.
I have these targets. They are small (See photo attached). I want to use them as scale rather than GPS. Meaning Target 1 = 0cm,Target 2= 0+5cm, Target 3= 5+5cm etc… But the targets are not in one straight line. So I was wondering if there is a way on Pix4D to do this. Use scale rather than GPS coordinates.

Hi Fia,
I am not 100% sure what you are trying to achieve. However it sounds like you want to add scale constraints to the project. This will keep your project scaled correctly. You might want to look at this article.


Thank you Mike_K! I will try!

I have tried scaling my project. This is a wall. Can you tell me why it is bowled shaped when it is supposed to be a flat/straight? I used 2 scale constraints (one horizontal to the top and one diagonal).

This is typically caused by some camera optimization errors. Try reprocessing but set your Internal Parameters Optimization to All Prior.

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I did this step but it is still circular in shape. Any other options?

I have another option that might help. First you need to set the accuracy of your images to 0.02. Open the Image Properties editor and right click on the horizontal and vertical accuracies. Change to 0.02.

Then change your Calibration methods to Accurate Geolocation and Orientation, and All Prior.

Try this and let us know how it processes.

Thank you Mike_K. Unfortunately, ”All images must be geolocated and oriented to use the Accurate Geolocation and Orientation calibration method” so I was not able to use it.

What kind of camera are you using? This sounds like a very unique project. Can you elaborate?

Thank you Mike for all your help thus far.

I am using a DSLR Camera- Canon EOS KissX7. I am attempting to model an indoor wall on Pix4DMapper. I am using the mini targets above as my GCPs. So I took many images of the wall, I measured the distances between the targets and those were the lengths I used between the GCPs. I followed the steps in this webinar to do that (Indoor Mapping Webinar by Pix4D - YouTube). I am not sure which step I went wrong to have my model concaving like that.

Hi Fia,
Can you upload your quality report?

wall version 2 using scale constraint PC2 _report.pdf (1.3 MB)

Hi Fia,
This is an interesting project that you have. The first thing I noticed are the number of images that you acquired. While I do not know the scale of your project, it appears to be an excessive number given the size of the project. My first thought is that it should be in the range of 100 images.

Another issue that can cause problems is the lack of texture in your images. Photogrammetry works best when there is a lot of image content. Without seeing your raw images it appears that this might be lacking a bit.

Have you considered using our mobile application called PIX4Dcatch? It is supported on both iOS and Android. This might work best for your needs. You can always do a free trial.