[GRASS-user] Compute volume of water using depth vector points.

[Nagesh Bhatkar]

r.volume outputs'  Total volume = 0

Prior to v.surf.rst ,
I used r.digit to create a MASK to select region of interest by hand in 
the imported raster map.
Then ran v.surf.rst by inputting the digitized vector point map and the 
MASK created.
Gave an interpolated raster map for the selected region.
Then used r.clump to create a clump raster containing 27 clumps by 
inputing interpolated raster.
Then ran r.volume and inputed the interpolated raster and this clump raster.
Result was as follows:

Volume report on data from surfoutdigit using clumps on surfclump map

 Cat         Average   Data   # Cells        Centroid                   
Total
Number  in clump  Total  in clump   Easting   Northing     Volume

    1         1.00       90521   90521       76.30        
9.93               0.00
    2         2.00      113958   56979       76.30        
9.93              0.00
    3         3.00      144480   48160       76.30        9.93           
   0.00
    4        4.00      189556   47389       76.30        9.93            
  0.00
    5        5.00       308695   61739       76.30        
9.93              0.00
    6        6.00      1306716  217786       76.30        
9.93             0.00
    7        7.00      400414   57202       76.30        9.93           
   0.00
    8        8.00      211728   26466       76.30        9.93            
  0.00
    9        5.00      506595  101319       76.30        9.93           
   0.00
   10        4.00     784616  196154       76.29        9.93             
0.00
   11        3.00     88668   29556       76.29        9.93              
0.00
   12       2.00      41640   20820       76.29        9.93             0.00
   13       1.00      18870   18870       76.29        9.93             0.00
   14       5.00      11560    2312       76.29        9.93             0.00
   15       7.00     1309735  187105     76.30        9.93             0.00
   16      -1.00        -1       1              76.29        
9.93            -0.00
   17      -1.00        -1       1             76.29        
9.93            -0.00
   18      -1.00        -2       2             76.29        
9.93            -0.00
   19      -1.00        -2       2              76.29        
9.93            -0.00
   20      -1.00      -127     127             76.29        
9.93            -0.00
   21      -1.00        -1       1              76.29        
9.93            -0.00
   22      -1.00        -2       2              76.29        
9.93            -0.00
   23      -1.00        -2       2               76.29        
9.93            -0.00
   24      -1.00     -1330    1330       76.29        9.93            -0.00
   25       5.00     39830    7966       76.30        9.93             0.00
   26       6.00         6       1               76.30        
9.93             0.00
   27       5.00         5       1               76.30        
9.93             0.00
                                                       Total Volume 
=           0.00

Where am i going wrong? kindly help.



Regards
Nagesh




Moritz Lennert wrote:
> On 05/08/08 06:37, Nagesh Bhatkar wrote:
>> Dear all,
>>
>> I imported and digitized a hydrographic chart for depth vector points 
>> in the ocean and
>> vector lines along the coast enclosing these ocean waters.
>> I am looking to  the interpolate these randomly digitized depth points
>> over a grid of any resolution and then later compute the volume of 
>> the water in the ocean
>> channel  between two land masses.
>> Which modules of GRASS GIS would help me accomplish the above two tasks.
>
> Interpolation:
> v.surf.rst
> v.surf.idw
> r.surf.nnbathy (Add-On)
> etc
>
> volume calculation:
> r.volume
>
> Moritz
>
>