[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
-------------------------+-------------------------
 Reporter:  mlennert     |      Owner:  grass-dev@…
     Type:  defect       |     Status:  new
 Priority:  normal       |  Milestone:  7.2.0
Component:  Raster       |    Version:  svn-trunk
 Keywords:  r.texture    |        CPU:  Unspecified
 Platform:  Unspecified  |
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 This is ok:

 {{{
 r.in.ascii in=- out=test_matrix <<EOF
 north: 3
 south: 0
 east: 3
 west: 0
 rows: 3
 cols: 3
 1 1 1
 3 0 2
 0 0 3
 EOF
 r.texture -s test_matrix out=text method=idm
 r.stats -1n text_IDM_90
 0.46666667
 }}}

 But this isn't:


 {{{
 r.in.ascii --o in=- out=test_matrix <<EOF
 north: 3
 south: 0
 east: 3
 west: 0
 rows: 3
 cols: 3
 1 1 1
 3 0 0
 0 0 3
 EOF
 r.texture -s test_matrix out=text method=idm --o
 r.stats -1n text_IDM_90
 0.48333332
 }}}

 The result should be 0.4.

 Testing shows that this always seems to happen when the series of values
 is discontinuous, as in the second case where we have 0, 1, 3, but no 2.

 I really have no time right now to look into this, but if someone with
 some knowledge of that module could, this would be great, especially if we
 could fix this before 7.2...

 And, yes, the above is a nice start for implementing tests...

 I can provide a spreadsheet where a colleague of mine has done the IDM
 calculations by hand for a series of matrices (comparing GRASS (almost all
 correct, yeah !) with PCI Geomatica (really weird results) and eCognition
 by-object texture variables (fairly similar to GRASS 3x3 texture means by
 object when the objects are above a certain size)).

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