# Volume Calculation

Global Mapper User
edited January 2012
Hello all,

I want to use the Global Mapper for volume calculations.
My question is, which formula is used in GB for volume calculation.
Or how will the volume computed. PixelSize * Height or other algorithm?

Thanks

edited April 2009
The volume calculations are done in Global Mapper by breaking the area being calculated for into many small squares, then using the formula you mentioned, Height * Pixel Size.

Let me know if I can be of further assistance.

Thanks,

Mike
Global Mapper Support
support@globalmapper.com
• Global Mapper User
edited January 2012
I have certain questions when it comes to Volume calculations, Grids?

1. Can GM compute a complete TIN Models consisting of points above 2 million?

2. How to calculate cut and fill between two surfaces?

3. And if possible, can I delete the triangles in areas where I dont want to have a surface created there. If yes then how?

4. Can user-defined Grids be computed from a particular surface and exported to DGN or DWG formats? If yes, then how?

I am new to GM, and as yet I really like the software, therefore , your proper guidance to my questions can only increase my faith in GM.

Regards,
Paul
edited January 2012
Paul,

Yes, Global Mapper should be able to handle TINs of that size with no problem, although you will be able to handle much larger ones using the 64-bit version of Global Mapper. If you already have the TIN loaded, just select the triangles you don't want with the Digitizer Tool and mark them as deleted, then right-click on the TIN layer in the Control Center and select to create an elevation grid with flattened areas. The areas inside the deleted triangles should not be filled.

You can export any loaded or created grid to 3D DXF Face, Point, and Mesh files using the File->Export Elevation Data menu command. If you use File->Generate Contours to create contours from the grid you can then export that to vector DXF or DWG files using File->Export Vector Data.

To find the volume between two surfaces, first use File->Combine Terrains to create a difference surface, then do the cut-and-fill against that difference surface with a cut height of 0.

Let me know if I can be of further assistance.

Thanks,

Mike
Global Mapper Guru
gmsupport@bluemarblegeo.com
http://www.globalmapper.com