# Volume Difference of an Area Surveyed over different Time Periods

Pix4Dmapper can be used to calculate the volume difference of an area surveyed at two moments in time. The images of each flight need to be processed in a separate project, in which the volume of the area at this moment in time is computed. Then, the results of these computations can be used to calculate the difference of volume of an area.

The following table describes different examples of Cut and Fill volumes. These are computed using Pix4Dmapper for a mining area that has been surveyed with two flights (flight1: before excavation / deposit, flight2: after excavation / deposit).

Legend
Black line: The stockpile volume that is drawn in the Volumes view.
Before: The project made using the first flight.
After: The project made using the second flight.
Cut: The Cut volume as calculated by Pix4Dmapper (positive value).
Fill: The Fill volume as calculated by Pix4Dmapper (negative value).
Total: The Total volume given by Pix4Dmapper. It is computed by adding Cut and Fill volumes (Total = Cut + Fill).

 Figure 1. Total Volume as calculates by Pix4Dmapper.

Case A: cut volume only, extracted material Case B: cut volume only, added material

Cut Before                                      Cut After

Cut volumes have positive value.

Cut Before                                      Cut After

Cut volumes have positive value.

Volume Difference = Cut After - Cut Before.

Volume Difference has negative value: material was extracted.

Volume Difference = Cut After - Cut Before.

Volume Difference has positive value: material was added.

Case C: fill volume only, extracted material Case D: fill volume only, added material

Fill Before                                       Fill After

Fill volumes have negative value.

Fill Before                                        Fill After

Fill volumes have negative value.

Volume Difference = Fill After - Fill Before.

Volume Difference has negative value: material was extracted.

Volume Difference = Fill After - Fill Before.

Volume Difference has positive value: material was added.

Case E: cut and fill volume

Cut and Fill Before                                                                    Cut and Fill After

Cut volumes have positive value, Fill volumes have negative value.

Volume Difference = (Cut After - Cut Before) + (Fill After - Fill Before) =  (Cut After + Fill After) - (Cut Before + Fill Before) = Total After - Total Before

Volume Difference has negative value: material was extracted.

Volume Difference has positive value: material was added.

4 out of 14 found this helpful

### Article feedback (for troubleshooting, post here)

• Antonio Trabana

This article explains it is possible, yet it does not explain how.

• Holden (Pix4D)

Hi Antonio. Currently, this is a feature available for users with a Pix4D BIM license. More info HERE.

Otherwise, you can calculate these values independently and calculate the differences in another application like excel.

• HEBERTH RIBEIRO SANTOS

Please would like more details. I need to compare volume between two surveys in ore extraction area and, apart from the difference, see the model of this difference. Has as? Send me an email: heberthribeiro@gmail.com. Thanks.

Por favor, gostaria de ter mais detalhes. Preciso comparar volume entre dois levantamentos em área de extração de minério e, além da diferença, ver o modelo desta diferença. Tem como? Me envie e-mail: heberthribeiro@gmail.com. Obrigado.

• Holden (Pix4D)

Hi Hilberth. Do you have a specific question about the process? It may be worth considering a personal training session to help develop your workflow and ensure you are handling the data correctly. More information below.

https://www.pix4d.com/services/training-certification

• HEBERTH RIBEIRO SANTOS

Hi. I am a Pix4D certified student on 2019-11-09 and I can guarantee that this content is not taught. In this way, I ask you to look for a way to teach how I can compare and view the volume of ore extraction area on different dates. And it was not for lack of interest. I told the teacher what I needed to learn ... Thank you and look forward to this help.

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Oi. Eu sou aluno certificado pela Pix4D em 2019-11-09 e, posso garantir que este conteúdo não não ensinado. Desta forma, solicito que possam procurar um meio de ensinar como posso fazer a comparação e visualizar o volume de área de extração de minério em diferentes datas. E não foi por falta de interesse. Eu disse ao professor do que eu precisava aprender... Agradeço e fico ao aguardo desta ajuda.

• Holden (Pix4D)

Thanks for elaborating. Often in a class or workshop, the information is generalized to provide foundational knowledge. In cases where specific use cases and individualized workflows are of interest, it is best to get 1 on 1 training to ask specific questions. This is what I was referring to. Again if you have a specific question about the process I can try and provide you with an answer here as well.