[GRASS-dev] Re: [GRASS GIS] #807: r.watershed doesnt consider longer distance to diagonal neighbouring pixels

[GRASS GIS]

#807: r.watershed doesnt consider longer distance to diagonal neighbouring pixels
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  Reporter:  aread   |       Owner:  grass-dev at lists.osgeo.org
      Type:  defect  |      Status:  new                      
  Priority:  major   |   Milestone:  6.4.0                    
 Component:  Raster  |     Version:  6.4.0 RCs                
Resolution:          |    Keywords:  r.watershed              
  Platform:  All     |         Cpu:  All                      
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Comment (by hamish):

 Replying to [comment:11 helena]:
 > However, when running r.watershed with elev_lid792_1m in the nc_spm_08
 > data set I get this as the result for mfd (which looks great):
 > http://skagit.meas.ncsu.edu/~helena/grasswork/accum_mfd.png
 > [[BR]]
 >
 > but this is where the negative values are:
 > http://skagit.meas.ncsu.edu/~helena/grasswork/accum_mfd_neg.png
 > [[BR]]
 > why does it switch from positive to negative in the middle
 > of the slope even for the flow accumulation that apparently originates
 > on the top of the hill well inside the area?

 I suspect that it hasn't switched to negative, just that the color map is
 stale and needs to be recalculated. (the slopes steeper than the last time
 r.colors was run go beyond the current color rules and so get mapped to
 the default color (white))

 try re-running r.colors on it & d.redraw. and d.what.rast (or gui equiv)
 to query actual values.


 > Just a note that the man page has description and option twice,
 > this should be an easy fix.

 check the .tmp.html file in the module build dir. There's a chance that it
 didn't get cleaned and every time you rebuild another copy of the auto-
 generated help text gets appended. (I haven't seen that in a while, but
 maybe it's back)

 the actual second OPTIONs section in it gives a paragraph explaining each
 option, which is too much for the command line quick help but useful to
 have. shrug.


 regards,
 Hamish

-- 
Ticket URL: <https://trac.osgeo.org/grass/ticket/807#comment:12>
GRASS GIS <http://grass.osgeo.org>