[Qgis-user] Volume between two surfaces

[Pedro Venâncio]

Hi Carlos,

Thank you for your great tip!

I was thinking... creating masks to separate the negative valuesfrom the positive values​​of the raster 'Hight', I can get the excavation and landfill volumes, right?


Thanks!
Pedro





----- Original Message -----
From: Carlos Cerdán <sig.upagu at gmail.com>
To: qgis-user at lists.osgeo.org
Cc: 
Sent: Tuesday, March 5, 2013 11:16 PM
Subject: Re: [Qgis-user] Volume between two surfaces

One idea:

Use calculator on GRASS and do:

Surface 1 - Surface 2 = Hight

We have the heigth value on each cell, so now use r.sum:

Volume = r.sum (of Hight) * side of pixel ^2 (if cells are squares)

Of course, you must use a mask to boundary your area of interest

Carlos Cerdán


El 05/03/13 17:49, Pedro Venâncio escribió:
> Hi all,
>
> Is there any way to calculate the volume between two surfaces (two DEM rasters)?
>
> There are ways to calculate the volume between a surface and a particular height value (GRASS r.volume or SAGA Grid Volume) but I can not find how to calculate the volumes (landfill / excavation) between two DEM.
>
> Any tips?
>
> Thank you very much!
>
> Best regards,
> Pedro Venâncio
>
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> Qgis-user at lists.osgeo.org
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