Images not displayed from GCPs selection in Tie points (Pix4D v2.2)

PIX4Dmapper PIX4Dmapper Questions/Troubleshooting
21

Hello, thanks for the additional information and the screenshot:
Let me stary by saying that

  1. Your workaround (use the Basic Editor) is correct
  2. This article explains all possibilities when it comes to GCPs:

Regarding your comment:
" I can import the GCPs–above the incorrectly positioned surface (which is the cause of this whole issue, and what we’re trying to address). I can click on any of these GCPs to get the screen you have, except there are no image thumbnails below."
If the 3D model is not positioned well and is far from the GCPs (either in X/Υ or in Z), you are right that you will get no listed image thumbnails.

" I’m able to click around to get an an image containing the GCP–that is it on the top thumbnail shown below. But my screen doesn’t look like yours."
Once you find the image that contains the GCP, please click the follow button (New Tie Point button):

tiepoint
tiepoint575×802 114 KB

Does this work? Now, you should have the same interface as in my screenshot and you should be able to label the point as GCP, add its coordinates and mark it.
Let me know how it goes.
Have a nice day,
Christina

22

Thank you for the help. Yes, that approach worked. I see now you’re simply creating a MTP using that workflow, but calling it a GCP. I suppose this is obvious, I never thought of those workflows being the same, since I am always importing and using survey-grade GCP.

Thank you also for confirming that simply marking the GCPs a few times with the basic editor is also an acceptable approach.

This begs the question, though, why suggest this work around when a simpler comparable approach is available?

So my question is: what is the benefit of using the ray cloud vs. the basic editor? They both seem to function at any point (eg. after step 1). Why not simply import my GCP file after step 1 and use the basic editor to mark all my points? What am I losing by doing that, as opposed to just marking 2 points in the basic editor then using the ray cloud to finish the marking?

Thanks again for your help.

G

23

You are welcome! Glad to know I could help :slight_smile:

“This begs the question, though, why suggest this work around when a simpler comparable approach is available?”

There is no difference in terms of accuracy or quality of the results. It is just much easier to mark the GCPs in the rayCloud (if 3D model and GCPs are more or less aligned and the image thumbnails are listed for marking). For example, it would be quite time consuming to mark 50 GCPs in the Basic Editor. For only a few GCPs, the time spent with the 2 methods is comparable.

24

Very good. Thank you again for your help.

G

1 Like