3D surface volume

[DavidOrchard]

I need a little guidance/ help.

I've two  DSMs of the same area taken on different dates showing major erosion.

I want to calculate the volume of material lost (old DSM minus new DSM).

The surface volume tool assumes a flat plain for the second surface.

Any ideas world be appreciated.

thanks

David

[DarrenWiens2]

As a (possibly fairly accurate) rough estimate, you could simply subtract one surface from the other to get the height difference between pixels. L * W * H is volume, but this assumes your world is made of LEGO blocks the size of your pixels.

More accurately, convert your rasters to TINs, then either Surface Volume or Polygon Volume to get the volume for each surface. Subtract the difference. You may also want to look into Extrude Between.

[NeilAyres]

Once you have the tins,

use Surface Difference 3d

http://resources.arcgis.com/en/help/main/10.2/index.html#//00q900000020000000

The output is a polygon feature with a class of -1 or 1 representing those areas of +ve or -ve difference and the volume therein.