Calculate difference in volume between 2 different time data sets

PIX4Dmapper PIX4Dmapper Questions/Troubleshooting
1

Hello, 

I want to know if I set GCP and measure (survey) them, fly the area (dirt pile) and process that.  At some point in the future, a client will do some more dirt work either adding or removing to the pile, if I refly it with GCP can I get pix to calculate the difference? 

Is there a workflow for that published somewhere?

 

Thanks

2

I saw some article about that already but I wanted to expand on this with: 

Does it make a difference if I cannot use permanent GCP points due to the area being changed too much. can I survey in new and different GCP each time to tie the data together?

Thanks

3

Hi, 

Probably you refer to this article on how to compute the volume difference: https://support.pix4d.com/hc/en-us/articles/202559189 

If you have two projects at two different moments in time of the same area. The workflow I usually recommend is to compute the volume of the area of interest in each of them and then calculate the difference, e.g. in an Excel sheet.

If the base surface of the volume remains the same and you add or remove some volume from the pile, a trick is to export the base surface in one project and import it in the second, so that the comparison is more accurate. This will avoid clicking errors. 

As for the GCPs, I think it is not an issue as long as you use GCPs in both projects. The accuracy of the reconstruction will be similar in both, as long as the GCPs are well distributed over the area and if possible close to the volume of interest. 

Maybe other Community users who compare volumes regularly can share their workflow and tips too. :) 

1 Like
4

Hello, I have been tasked with calculating quantities on a large area and would rather do it with the drone and Pix4D vs walking. So here is my question: How can I fly a site one week and then fly it again a week later and get the volume difference between the two flights using Pix4D?

5

Hello @jakermedlock,

I would suggest you refer to this article on how to compute the volume difference: https://support.pix4d.com/hc/en-us/articles/202559189

If you have two projects at two different moments in time of the same area. The workflow I usually recommend is to compute the volume of the area of interest in each of them and then calculate the difference, e.g. in an Excel sheet.

If the base surface of the volume remains the same and you add or remove some volume from the pile, a trick is to export the base surface in one project and import it in the second, so that the comparison is more accurate. This will avoid clicking errors.

As for the GCPs, I think it is not an issue as long as you use GCPs in both projects. The accuracy of the reconstruction will be similar in both, as long as the GCPs are well distributed over the area and if possible close to the volume of interest.

Regards,

6

Thank you so much for the response! Would using Pix4Dbim maybe be a better option for this? This type of calculation as well as doing as-builts is the majority of what my drone flights are for.

Thank you again for the response!

7

Hello @jakermedlock,

If you want to use the cloud platform. In that case, Pix4Dcloud Advance would be the best option for you because it will allow you to add the GCPs and provide the feature such as volume comparison. For more information, I would recommend you to go through our blog on Introducing Pix4Dcloud & Pix4Dcloud Advanced.

Just for your information, we no longer offered a Pix4Dbim license. However, the new Pix4Dcloud Advanced is equivalent to Pix4Dbim with additional features.

Best,

8

The link to the article provided above no longer exists, is there another link or article that would help with the volume calculations between two flights of the same area?