[GRASS-dev] [GRASS GIS] #2298: r.stream.order hack= generates order 1 single pixels

[GRASS GIS]

#2298: r.stream.order hack= generates order 1 single pixels
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 Reporter:  hcho            |       Owner:  grass-dev@…              
     Type:  defect          |      Status:  new                      
 Priority:  major           |   Milestone:  7.1.0                    
Component:  Raster          |     Version:  svn-trunk                
 Keywords:  r.stream.order  |    Platform:  Linux                    
      Cpu:  x86-64          |  
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Comment(by hellik):

 Replying to [comment:5 hellik]:
 > Replying to [hcho]:
 > > Unfortunately, accumulation map didn't help. I got the same result.
 Maybe, flow direction map is still used for calculating orders? and
 accumulation map is optional for doing something else...?
 >
 > what about your region settings? the region and resolution should be
 > aligned to the DEM, e.g. g.region -a rast=yourDEM align=yourDEM.

 tested here with different DEM (10x10m, 25x25m, 35x35m, 100x100m) and
 different thresholds for river extraction, can't reproduce the report.

 for the record, beside the region settings, the manual states:

 {{{
 The module can work only if direction map, stream_rast map and the
 computational region have the same settings. It is also required that the
 stream_rast map and the direction map come from the same source. For lots
 of reason this limitation probably cannot be omitted. This means if
 stream_rast map comes from r.stream.extract also the direction map from
 r.stream.extract must be used. If stream network was generated with MFD
 method also MFD direction map must be used.
 }}}

 regarding accumulation map:

 {{{
 Optional input flow accumulation map may be produced by r.watershed or
 r.stream.extract. This map is an option only if Horton's or Hack's
 ordering is performed. Normally both Horton and Hack ordering is
 calculated on cumulative stream length which is calculated internally.
 Flow accumulation can be used if user wants to calculate the main channel
 as the stream with the highest value of aqccumulation.
 }}}

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Ticket URL: <https://trac.osgeo.org/grass/ticket/2298#comment:7>
GRASS GIS <http://grass.osgeo.org>