[GRASS-dev] [GRASS GIS] #2856: i.segment: warning "Region consists of only one cell, nothing to update" slows down module

[GRASS GIS]

#2856: i.segment: warning "Region consists of only one cell, nothing to update"
slows down module
------------------------------+-------------------------
 Reporter:  mlennert          |      Owner:  grass-dev@…
     Type:  defect            |     Status:  new
 Priority:  normal            |  Milestone:  7.0.4
Component:  Imagery           |    Version:  svn-trunk
 Keywords:  i.segment region  |        CPU:  Unspecified
 Platform:  Unspecified       |
------------------------------+-------------------------
 In the NC dataset:


 {{{
 g.region n=221318 s=220073 w=637746 e=639646 res=1
 i.group ortho in=ortho_2001_t792_1m
 i.segment group=ortho at user1 output=ortho_seg_001 threshold=0.01
 memory=2500
 }}}

 Then, when I try to use the output of this as seeds for the next level:


 {{{
 i.segment group=ortho at user1 output=ortho_seg_002_seeded threshold=0.02
 seed=ortho_seg_001 memory=2500
 }}}

 I get tons of

 {{{
 WARNING: Region consists of only one cell, nothing to update
 }}}

 The module run takes +/- 1m25.

 When I comment
 [https://trac.osgeo.org/grass/browser/grass/trunk/imagery/i.segment/create_isegs.c#L1086
 line 1086]  in imagery/i.segment/create_isegs.c so that the warning is not
 issued, module run only takes about 20s.

 Is this warning really necessary ? Or is it a bug that it appears in this
 context ?

--
Ticket URL: <https://trac.osgeo.org/grass/ticket/2856>
GRASS GIS <https://grass.osgeo.org>