[GRASS-dev] [GRASS GIS] #3694: WHERE statement in v.generalize do not work

[GRASS GIS]

#3694: WHERE statement in v.generalize do not work
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  Reporter:  BastienFR  |      Owner:  grass-dev@…
      Type:  defect     |     Status:  new
  Priority:  normal     |  Milestone:
 Component:  Default    |    Version:  7.4.1
Resolution:             |   Keywords:  v.generalize
       CPU:  x86-64     |   Platform:  MSWindows
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Comment (by mmetz):

 Replying to [comment:3 BastienFR]:
 > Thanks for your answer.  I did try with the good option `layer=1`
 directly in GRASS and it worked as expected.  I'll update my question on
 StackExchange to give the answer (or if you want to do it, I'll accept
 your answer).

 You can update your question to give the answer, maybe with a link to the
 manual and the (by now updated) tutorial ;-)
 >
 > However, note that your tutorial do not state that properly
 (https://grasswiki.osgeo.org/wiki/V.generalize_tutorial#Gereneral_Parameters).
 There is no `layer` option in the call given.
 >
 > {{{
 > v.generalize -c input=roads output=roads_douglas_reduction2
 method=douglas_reduction threshold=0 reduction=50 type=line where="cat<3"
 > }}}

 Thanks for pointing this out, now fixed.

 The tutorial has been written for the initial version of v.generalize
 where the default answer for the layer option was 1. The default has been
 changed from 1 to -1 (all layers) in r39888 (9 years ago).
 >
 > The fact the the QGIS v.generalize tool do not allow to set the `layer`
 option even if allowing setting the `WHERE` statement, how or where should
 we document the problem so it's fix there?

 The QGIS interface description for v.generalize needs to have layer=1
 hard-coded (not a user-option).

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Ticket URL: <https://trac.osgeo.org/grass/ticket/3694#comment:4>
GRASS GIS <https://grass.osgeo.org>