[GRASS-user] Problem with r.basin in grass7

[Helmut Kudrnovsky]

> c) Try to use the NC dataset

now tested here with NC dataset (see also
http://grasswiki.osgeo.org/wiki/R.basin; the coordinates are taken from the
wiki)

r.info map=elevation at PERMANENT                                                  

+----------------------------------------------------------------------------+
 | Map:      elevation at PERMANENT            Date: Tue Nov  7 01:09:51 2006   
|
 | Mapset:   PERMANENT                      Login of Creator: helena         
|
 | Location: nc_spm_08_grass7                                                
|
 | DataBase: C:\grassdata                                                    
|
 | Title:    South-West Wake county: Elevation NED 10m ( elev_ned10m )       
|
 | Timestamp: none                                                           
|

|----------------------------------------------------------------------------|
 |                                                                           
|
 |   Type of Map:  raster               Number of Categories: 255            
|
 |   Data Type:    FCELL                                                     
|
 |   Rows:         1350                                                      
|
 |   Columns:      1500                                                      
|
 |   Total Cells:  2025000                                                   
|
 |        Projection: Lambert Conformal Conic                                
|
 |            N:     228500    S:     215000   Res:    10                    
|
 |            E:     645000    W:     630000   Res:    10                    
|
 |   Range of data:    min = 55.57879  max = 156.3299                        
|
 |                                                                           
|
 |   Data Description:                                                       
|
 |    generated by r.proj                                                    
|
 |                                                                           
|
 |   Comments:                                                               
|
 |    r.proj input="ned03arcsec" location="northcarolina_latlong" mapset="\  
|
 |    helena" output="elev_ned10m" method="cubic" resolution=10              
|
 |                                                                           
|

+----------------------------------------------------------------------------+

then

g.region -p -a rast=elevation at PERMANENT align=elevation at PERMANENT               
projection: 99 (Lambert Conformal Conic)
zone:       0
datum:      nad83
ellipsoid:  a=6378137 es=0.006694380022900787
north:      228500
south:      215000
west:       630000
east:       645000
nsres:      10
ewres:      10
rows:       1350
cols:       1500
cells:      2025000
(Thu Nov 20 11:29:22 2014) Befehl ausgeführt (4 Sek)  

 and 

r.basin --verbose map=elevation at PERMANENT prefix=a
coordinates=636654.791181,218824.126649 dir=C:\tmp\rbasin threshold=40
[...]
(Thu Nov 20 11:40:48 2014) Befehl ausgeführt (7 Min 0 Sek)     

r.basin finishes. as Margherita already mentioned, the region resolution has
to be aligned to the DEM resolution.

have a look at r.info map=elevation at PERMANENT  :

 |   Comments:                                                               
|
 |    r.proj input="ned03arcsec" location="northcarolina_latlong" mapset="\  
|
 |    helena" output="elev_ned10m" method="cubic" resolution=10    

that can be a starting point for the reprojection of your NED DEM (in
geographic coordinates) to a projected location.

HTH



-----
best regards
Helmut
--
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