sub project at different dates

PIX4Dcloud
1

I would like to capture at different dates the same location in order to be able to compute volume and compare them.
My workflow Pix4DCatch + iPhone 12 Pro (without Vidoc GNSS antenna) + Pix4DCloud => 3D models will be known approximately in xyz.
I’ll use 4 or 6 points visibles in the field during each capture at different dates These points will be present for each capture.
It would be interested to use these points, I would say like GCP, order to be sure the 3D model will match together if I want to compare volume between two date.
Do you think it will be possible to develop this feature? Or is there a way to do so?

2

Hi totalsurvey2-nnn,

Welcome to the community.

It is possible to compare data between multiple captures from the same site in PIX4Dcloud Advanced. Please check out the following documentation and let me know if you have any further questions.

Timeline - PIX4Dcloud Advanced
Compare volumes PIX4Dcloud Advanced
2D Comparison - PIX4Dcloud Advanced

While you are exploring, you might want to compare PIX4Dsurvey as well.

-Jon

3

----- Message transmis -----

4

Hi Jonathan,

Thanks for your response.

I’m aware of these possibilities to compare ortho or volumes.

But my concern is another point.

Let me share my project: PIX4Dcloudand PIX4Dcloud

As you can see I have 2 3D models captured at two dates. I’m not using gcp ou Vidoc antenna. The 2 models are not at the same place. There is an offset of around 3 m between them.

My suggestion was to able to use benchmark as shown on the screenshot below (photo ont he right with a green cross on a steel peg colored in orange) in the 2 3D models in order to make them match, but without the CGP method. I would say rather with the tie points method.

In that way, it will be possible to fit the models the ones to the others by declaring the steel peg in the 2 sub projects.

Stéphanehttps://cloud.pix4d.com/site/147149/dataset/1082176/model?shareToken=6e354796-36e8-4347-80c0-86612f78c400

5

Hi Stephane,

There is a way to make this happen by marking MTPs in a base project, converting them to GCPs to then export and use in subsequent captures at the same site.

This comes with a few caveats:

  • Without the use of GCPs and/or RTK compatible devices the absolute accuracy of the project will be limited to the accuracy of the device GPS. This will also affect any calculations made.
  • You will need at least 5 target points(more for larger areas) that are easy to locate, and will not move for the entire project.
  1. Create a new/base project.

  • Distribute the immovable target points as you would place GCPs.

  • Capture the project area. This will be your baseline. It is advisable to complete in the best conditions possible.

  • Import project into PIX4Dmapper, and process Step 1.

  1. Mark MTPs
  1. Open the GCP/MTP Manager
  • Select all of the MPTs.
  • Right-click on any selected Manual Tie Point in the Type column.
  • Select Edit Types in Selected Rows .
  • Select 3D GCP in the dropdown menu.
  • Click the Export GCPs… button.
  • Choose an appropriate name and location for the file, and click OK .

You now have a .csv file you can use to import into subsequent captures at the same location to align each to the other. Be sure to use the same coordinate reference systems between projects. Refer to How to import and mark ground control points (GCPs) for more information.

I hope this information proves helpful.

Regards,

-Jon

6

Hi Jonathan,

Thank you for your answer.

Your informations are helpful. However, this workflow seems to be the one for Mapper. What about the same type of workflow for Pix4DCloud?

Indeed, in PIX4DCloud I didn’t find the way to enter GCPs manuallly. The only option consists to import a file containing a GCPs list and the process should be able to detect the GCPs after introducing the diagonal measurement of the targets.
I did that with a diagonal target of 18cm, but the loud process is not able to detect them and worst, sometime the process never ends.

Best regards

Stephane

| Jonathan Dennis Jonathan_Dennis Technical Support Engineer
March 2 |

  • | - |

Hi Stephane,

There is a way to make this happen by marking MTPs in a base project, converting them to GCPs to then export and use in subsequent captures at the same site.

This comes with a few caveats:

  • Without the use of GCPs and/or RTK compatible devices the absolute accuracy of the project will be limited to the accuracy of the device GPS. This will also affect any calculations made.
  • You will need at least 5 target points(more for larger areas) that are easy to locate, and will not move for the entire project.
  1. Create a new/base project.

  • Distribute the immovable target points as you would place GCPs.

  • Capture the project area. This will be your baseline. It is advisable to complete in the best conditions possible.

  • Import project into PIX4Dmapper, and process Step 1.

  1. Mark MTPs
  1. Open the GCP/MTP Manager
  • Select all of the MPTs.
  • Right-click on any selected Manual Tie Point in the Type column.
  • Select Edit Types in Selected Rows .
  • Select 3D GCP in the dropdown menu.
  • Click the Export GCPs… button.
  • Choose an appropriate name and location for the file, and click OK .

You now have a .csv file you can use to import into subsequent captures at the same location to align each to the other. Be sure to use the same coordinate reference systems between projects. Refer to How to import and mark ground control points (GCPs) for more information.

I hope this information proves helpful.

Regards,

-Jon

7

Hi Stephane,

There is not a current PIX4Dcloud based workflow that can accomplish the goal given these parameters. One would need PIX4Dmapper to create the “digital” GCP file to import into PIX4Dcloud.

Regards,
Jon

8

Hi Jonathan,

I know this is not the based workflow. Please consider this request like a suggestion. Why not do have the possibility to select manually “GCPs” on images as the same way that Pix4DMapper. This functionality is missing.

Best regards,

Stephane

Skype: sroc2005

9

Hi Stephane,

Absolutely, thank you for clarifying. I will post this request internally, but would highly suggest submitting the same on the PIX4Dcloud Community feature request page. In this way, more users can contribute to your idea by voting. Key stakeholders responsible for our products’ development check our Community regularly to decide about the product development.

Your feedback is greatly appreciated, thank you.

-Jon