[GRASS-dev] [GRASS GIS] #3210: r.texture: bug when non continuous series of values

[GRASS GIS]

#3210: r.texture: bug when non continuous series of values
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  Reporter:  mlennert     |      Owner:  grass-dev@…
      Type:  defect       |     Status:  reopened
  Priority:  normal       |  Milestone:  7.2.0
 Component:  Raster       |    Version:  svn-trunk
Resolution:               |   Keywords:  r.texture
       CPU:  Unspecified  |   Platform:  Unspecified
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Comment (by mmetz):

 Replying to [comment:28 mlennert]:
 > Replying to [comment:27 mmetz]:
 > >
 > > We could remove cropping at margins, the results would not be perfect,
 but better than nothing.
 >
 > That's debatable. In my colleagues tests we saw that PCI Geomatica
 "solves" this problem by just replicating the margin row/col as many times
 as necessary depending on window size. This leads to weird textures at the
 margins.

 Inventing values is a bad idea.
 >
 > Another (IMHO preferrable) option would be to calculate the texture with
 just the available pixels, but this would mean that for a 3x3 window you
 would only have one neighbor in each direction (except for the n-s or
 e-w). Don't know if this is an issue ?

 I would use just the available pixels, the question is then more general,
 how to handle NULL cells, also inside the current region. If NULL cells
 are allowed, there is no reason to crop at the margins. If NULL cells are
 not allowed, any moving window that contains NULL cells would be skipped,
 also very large moving windows with only a single NULL cell. Therefore I
 would prefer to allow NULL cells.

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Ticket URL: <https://trac.osgeo.org/grass/ticket/3210#comment:31>
GRASS GIS <https://grass.osgeo.org>