[GRASS-user] How to calculate the area of a rastermap

[opopanax]

Thank you all,
I wanted to calculate the extent of an area

r.report units=k
is a very nice one and much more better than r.stats

r.surf.area
works as well

 From g.region and r.info I didn't get the information I wanted

Cheers
om shantih
Philipp

_Examples:_

GRASS:~$ r.report wo_08 uni=k
r.stats:  100%
+-----------------------------------------------------------------------------+
|                         RASTER MAP CATEGORY 
REPORT                          |
|LOCATION: wertach_gk_221207                          Tue Jan 15 
08:11:22 2008|
|-----------------------------------------------------------------------------|
|          north: 5367102.02878204    east: 
4423032.52391016                  |
|REGION    south: 5262609.45830234    west: 
4370953.43615398                  |
|          res:        30.00073801    res:       
29.99947451                  |
|-----------------------------------------------------------------------------|
|MASK:none                                                                    
|
|-----------------------------------------------------------------------------|
|MAP: (untitled) (wo_08 in 
x02_landsat)                                       |
|-----------------------------------------------------------------------------|
|                      Category Information                        |  
square  |
|#|description                                                     
|kilometers|
|-----------------------------------------------------------------------------|
|1| . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
.|1215.11661|
|*|no data. . . . . . . . . . . . . . . . . . . . . . . . . . . . 
.|4226.76114|
|-----------------------------------------------------------------------------|
|TOTAL                                                             
|5441.87775|
+-----------------------------------------------------------------------------+


GRASS:~$ r.surf.area wo_08

Null value area ignored in calculation 4.226761e+09
Plan area used in calculation: 5.437182e+09
Surface Area Calculation(low, high, avg):
        1.208337e+09 1.208337e+09 1.208337e+09
Current Region plan area: 5.441878e+09
Estimated Region Surface Area: 1.209381e+09

Done.


GRASS:~$ r.info wo_08
 +----------------------------------------------------------------------------+
 | Layer:    wo_08                          Date: Mon Jan 14 08:04:30 
2008    |
 | Mapset:   x02_landsat                    Login of Creator: 
om              |
 | Location: 
wertach_gk_221207                                                |
 | DataBase: 
/home/om/grassdata                                               |
 | Title:     ( wo_08 
)                                                       |
 | timestamp: 
none                                                            |
 |----------------------------------------------------------------------------|
 |                                                                            
|
 |   Type of Map:  raster               Number of Categories: 
1               |
 |   Data Type:    
CELL                                                       |
 |   Rows:         
3483                                                       |
 |   Columns:      
1736                                                       |
 |   Total Cells:  
6046488                                                    |
 |        Projection: Transverse Mercator (zone 
0)                            |
 |            N: 5367102.02878204    S: 5262609.45830234   Res: 
30.00073801   |
 |            E: 4423032.52391016    W: 4370953.43615398   Res: 
29.99947451   |
 |   Range of data:    min = 1  max = 
1                                       |
 |                                                                            
|
 |   Data 
Source:                                                             |
 |                                                                            
|
 |                                                                            
|
 |                                                                            
|
 |   Data 
Description:                                                        |
 |    generated by 
r.water.outlet                                             |
 |                                                                            
|
 |                                                                            
|
 +----------------------------------------------------------------------------+

GRASS:~$ g.region -p
projection: 99 (Transverse Mercator)
zone:       0
datum:      potsdam
ellipsoid:  bessel
north:      5367102.02878204
south:      5262609.45830234
west:       4370953.43615398
east:       4423032.52391016
nsres:      30.00073801
ewres:      29.99947451
rows:       3483
cols:       1736
cells:      6046488



Hamish wrote:
> Philipp Steigenberger wrote:
>   
>>>  I know there is a posibility to calculate the area of a rastermap,
>>> but I cannot find the command.
>>>
>>>  I have a water.outlet map. The area data range is 1 to 1
>>>       
>
> Carlos wrote:
>   
>> r.surf.area?
>> r.stats?
>>     
>
> 'r.report units=h' too
>
>
> Hamish
>
>
>
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