[GRASS-dev] [GRASS GIS] #1924: r.watershed - empty stream segment map

[GRASS GIS]

#1924: r.watershed - empty stream segment map
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 Reporter:  jradinger  |       Owner:  grass-dev@…              
     Type:  defect     |      Status:  new                      
 Priority:  normal     |   Milestone:                           
Component:  Raster     |     Version:  svn-trunk                
 Keywords:             |    Platform:  Linux                    
      Cpu:  x86-32     |  
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Comment(by jradinger):

 I just checked an the region matches:


 {{{
 |   Type of Map:  raster               Number of Categories: 0
 |
  |   Data Type:    DCELL
 |
  |   Rows:         140
 |
  |   Columns:      190
 |
  |   Total Cells:  26600
 |
  |        Projection: UTM (zone 13)
 |
  |            N:    4928000    S:    4914000   Res:   100
 |
  |            E:     609000    W:     590000   Res:   100
 |
  |   Range of data:    min = 0  max = 16433.8095116624
 |
  |
 |
  |   Data Description:
 |
  |    generated by r.cost
 }}}

 Two more important things:
 1) The elevation input map is accutally already a thinned river raster.
 The raster
 values represent a pseude elevation which  was generated with r.cost from
 the source.
 Thus the value (elevation) is increasing upstream. r.watershed is just
 used for getting
 the flowdirection and segmenting the river raster. (if needed I can
 provide the elevation-rcost
 raster)

 2) I tried r.watershed with treshold=1 and that is working perfectly

 And maybe a warning/error message should be printed when threshold = 0,
 instead of the (for me confusing error)

-- 
Ticket URL: <http://trac.osgeo.org/grass/ticket/1924#comment:2>
GRASS GIS <http://grass.osgeo.org>