[GIS] Estimation of volume from DTM

demqgissagavolume

I'm using QGIS for quite a while now but I'm having some problems in measuring the volume of a depression zoned North of a waste dump I'm studying.

For the analysis I'm using a recent 1mx1m DTM of the area:

enter image description here

As I said the main element of the study is an estimation of the volume of the depression North of the dump. Here's the hillside of the area:

enter image description here

where I highlighted the boundaries of the depression.

As tool for the estimation I used the SAGA GIS tool Raster Volume in Qgis.

As Input GRID information I used the 1mx1m DTM but after running it on the log message panel here's the result: 

Usage: saga_cmd grid_calculus 2 [-GRID <str>] [-METHOD <str>] [-LEVEL <str>]
            -GRID:<str>     Grid
            Grid (input)
            -METHOD:<str>   Method
            Choice
            Available Choices:
            [0] Count Only Above Base Level
            [1] Count Only Below Base Level
            [2] Subtract Volumes Below Base Level
            [3] Add Volumes Below Base Level
            Default: 0
            -LEVEL:<str>    Base Level
            Floating point
            Default: 0.000000*

I used the "Count only above base level" method considering the lowest point of the DTM as base level, but as you can see the result is a 0 value volume.

Am I mistaking anything? Here is the .asc DTM.

Best Answer

Using QGIS 2.18.3, it seems to work fine.

I set the "County Only Above Base Level", with base level equals to 0 and I get this log:

Algorithm Raster volume starting...
grid_calculus "Grid Volume" -GRID "C:\Users\xxxxx\AppData\Local\Temp\processingdd38dbc0f5ec434f922835f11ed2d9d0\3ddfa5d81c1744819d54de14d3c7a8f1\DTMdiscarica.sgrd" -METHOD 0 -LEVEL 0

C:\OSGeo4W\bin>set SAGA=C:/OSGeo4W/apps\saga

C:\OSGeo4W\bin>set SAGA_MLB=C:/OSGeo4W/apps\saga\modules

C:\OSGeo4W\bin>PATH=C:\OSGeo4W\apps\Python27\lib\site-packages\Shapely-1.2.18-py2.7-win32.egg\shapely\DLLs;C:\OSGeo4W\apps\Python27\DLLs;C:\OSGeo4W\apps\qgis\bin;C:\OSGeo4W\bin;C:\Windows\system32;C:\Windows;C:\Windows\WBem;C:\OSGeo4W\apps\msys\bin;C:\OSGeo4W\apps\Python27\Scripts;C:/OSGeo4W/apps\saga;C:/OSGeo4W/apps\saga\modules

C:\OSGeo4W\bin>saga_cmd grid_calculus "Grid Volume" -GRID "C:\Users\xxxxx\AppData\Local\Temp\processingdd38dbc0f5ec434f922835f11ed2d9d0\3ddfa5d81c1744819d54de14d3c7a8f1\DTMdiscarica.sgrd" -METHOD 0 -LEVEL 0
ERROR 1: Can't load requested DLL: C:\OSGeo4W\apps\saga\dll\gdal_MrSID.dll
127: Impossibile trovare la procedura specificata.


ERROR 1: Can't load requested DLL: C:\OSGeo4W\apps\saga\dll\gdal_MrSID.dll
127: Impossibile trovare la procedura specificata.


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_____________________________________________

_____________________________________________
library path: C:\OSGeo4W\apps\saga\modules\grid_calculus.dll
library name: Grid - Calculus
tool name : Grid Volume
author : (c) 2005 by O.Conrad
_____________________________________________

Load grid: C:\Users\xxxxx\AppData\Local\Temp\processingdd38dbc0f5ec434f922835f11ed2d9d0\3ddfa5d81c1744819d54de14d3c7a8f1\DTMdiscarica.sgrd...




Parameters


Grid system: 1; 1290x 1792y; 624079.089172x 4919509.290207y
Grid: DTMdiscarica
Method: Count Only Above Base Level
Base Level: 0.000000



Grid Volume: Volume: 890177920.097229

C:\OSGeo4W\bin>exit
Converting outputs
Loading resulting layers
Algorithm Raster volume finished

So, I get Volume: 890177920.097229 (I think it's expressed in the project units).

EDIT Before running the algorithm, remember to check this option from Processing > Options:

enter image description here

Otherwise, you won't see any result.

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