# Volumetric Accuracy of stocks

Hi, Iv been asked to work out a volumetric accuracy for some stocks. Could some one point me in the correct direction?

I’m sure the answer is in the quality report but im not sure.

Hi,

You should look at the Total volume error in Pix4Dmapper Volume tab as in the example below:

Pix4Dmapper estimates the error of a volume calculation. The degree of error within the volume calculations depends on the spatial resolution of the GSD. Therefore, based on the GSD you have in your project, the volume error will be calculated.

1. To calculate the error of a volume, the error for each cell of the volume has to be computed first.
• Each cell has X, Y, Z direction. The errors on the X and Y direction is estimated to be 0 but for Z is 1,5 times the GSD.
• As each cell of the volume base has the error on the X and Y direction - 0, the width and the length is equal to the GSD.
• Therefore:

Ei [the volume error of one cell] = GSD * GSD * 1.5 * GSD.
Read more in Error estimation in volume calculation.

Volume error of a cell.

1. Once the error for each cell is known, the error of the Cut, Fill, and Total volume is computed by summing the error of each cell.
Total Volume error = Cut Volume error + Fill Volume error

Cut Volume [units3]: Volume that is above the volume base.
Fill Volume [units3] : Volume that is below the volume base.
Total Volume [units3] : Total Volume = Cut volume + Fill volume.

I hope my answer helps you understand the calculation which in detail you can find in our articles:

Best!

Hi Beata,
In total Volume Error , 149,83m^3 It is not too much for excavation? It means that almost 10 small truck more . this can cause trouble. How can explain that to customer ?

What would you say about that?

Thank you!

Well, it’s hard for me to give an opinion on whether your calculation is correct as I didn’t look into your project calculation and verify it. You can share here the Quality Report so we can check the accuracy. Also, send us the screenshot of the full view of the Volumes tab.

Thanks!

Hi Beata;
I asked the question according to your screenshot , “In total Volume Error , 149,83m^3 It is not too much for excavation?” you can see the screen shot head of the page.

Thank you!

Oh, right.

I’m sorry to disappoint you, but I can’t give you an answer. I don’t remember from where I took this screenshot from, so I can’t double-check the accuracy. Yet, if you have any doubts about your results, we can together analyse them.

Regards