DEM model

[Mina]

Hello,

Regarding the volume measurement using the DEM model, it seems that model orientation in the coordinate system (can be seen in the model view), affects the consequent DEM model. It means that we have different DEM models if we have different orientations. It also affects the consequent volume measurement accuracy. How I can get the accurate volume measurement of an object which is located in a horizontal surface?

Mina

[Mina]

Hi,

I would like to make my question a bit clear. I calculated the volume of a box using the mesh and the result was very accurate but when I tried to measure the volume based on the DEM model, I did not get the same accuracy.
I don't know what is exactly the source of the error?
I have also another problem when I change the model orientation manually in Dense cloud, I also result in difference DEM models and different volumes of the same box!!

Mina

[Alexey Pasumansky]

Hello Mina,

DEM-based volume measurement calculates the volume in the selected extents defined by shape above/below the specified level. For your case Best fit plane may be optimal, I assume.

But if you are using mean level option applying it to the model oriented differently it of course will give you different values, because the cut off plane is different, since you are changing coordinate system axis orientation.
Note that custom level value in 1.3.0 build 3772 is working incorrectly, unless called form Python API.


Just a rough illustration of what I'm speaking about:

[Mina]

Hello Alexey,

Thanks for your response. I used the “Best fit plane” to measure the volume and came up with these results;
Volume above (m3): 8370.914
Volume below (m3): 1.542
Volume total (m3): 8369.372

The actual volume is 8000 m3 and the mesh-based volume measurement shows the value of 8082.95 m3. Why there is a noticeable difference between mesh- and DEM-based volume measurements? In other words, why DEM- based result is not that much accurate?

Mina