[GRASS-dev] Re: [GRASS GIS] #387: r.grow.distance, r.random.surface ignores raster MASK

[GRASS GIS]

#387: r.grow.distance, r.random.surface ignores raster MASK
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  Reporter:  marisn       |       Owner:  grass-dev at lists.osgeo.org
      Type:  defect       |      Status:  closed                   
  Priority:  major        |   Milestone:  6.4.0                    
 Component:  Raster       |     Version:  unspecified              
Resolution:  invalid      |    Keywords:                           
  Platform:  Unspecified  |         Cpu:  Unspecified              
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Changes (by glynn):

  * status:  new => closed
  * resolution:  => invalid

Comment:

 Replying to [ticket:387 marisn]:

 > When r.grow.distance or r.random.surface are run with enabled raster
 MASK, mask is used only to filter out input values but does not affect
 output maps (they contain also values in areas hidden by mask).

 > Display resulting maps -> areas OUTSIDE of MASK also contain some
 values. In r.random.surface case value in MASKed area is NOT random. As
 most GRASS modules will work only in not masked area, it's conterintuitive
 and requires additional processing to remove MASKed areas from output
 maps.

 Yes. That's how MASK works. That's how it '''always''' works.

 If you want to mask the '''result''' of an operation, you need to
 explicitly apply the mask by running e.g. r.resample while the mask is
 active.

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Ticket URL: <http://trac.osgeo.org/grass/ticket/387#comment:2>
GRASS GIS <http://grass.osgeo.org>