topic Re: Help Obtaining Volume Estimates in 3D Questions

Help Obtaining Volume Estimates

KariNishioka — Mon, 12 Mar 2012 22:58:01 GMT

*Sorry, should be under the Spatial Analyst thread*

Hi,

HELP.....I�??m trying to obtain dredging volumes based off of sounding points and toe depths for a project I've been assigned. The sounding points indicate the depth our harbor channels are currently at and the toe lines indicate what depth they should be at. My task is to see how much sediment needs to be removed and make visual renderings of it. I�??m not sure what the best approach is�?�cut/fill, surface volume, TIN difference�?�.

One of the challenges is the depths associated with the toe lines are in annotation form. So far I�??ve created a TIN off the sounding points, but I don�??t know what my next move should be. Do I need to somehow get z values assigned to the toe lines? I am pretty new at this, so any advice would be much appreciated. I am using arc 9.3.1.

Thanks in advance!

Re: Help Obtaining Volume Estimates

JeffreySwain — Tue, 13 Mar 2012 11:43:42 GMT

If the toe lines describe what it should be then you should create a TIN or interpolated raster surface based on the lines. You should make the lines 3d with the 3d Analyst toolbar or as described here.

Once the lines are 3d, then you should be able to compare the TIN to the new surface with the TIN Difference tool. You can also visualize the difference when comparing the two TINs and the polygon of the channel with the Extrude Between Tool.

The Cut/Fill tool or TIN Difference tool can both be used, for your analysis I would think the Cut/Fill would be more appropriate.

Re: Help Obtaining Volume Estimates

KariNishioka — Wed, 14 Mar 2012 04:34:11 GMT

Jeff, mahalo for your help. I'm about to try tackling this again and will let you know how it works for me.

Re: Help Obtaining Volume Estimates

JeffreySwain — Wed, 14 Mar 2012 11:37:28 GMT

Just be advised that the cut/fill requires the TINs to be converted to rasters and be mindful of the cell size when exporting. Otherwise it should create the desired output. Let me know how it works.