[GRASS-dev] Re: [GRASS GIS] #169: Request for r.edit

[GRASS GIS]

#169: Request for r.edit
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  Reporter:  cmbarton     |       Owner:  grass-dev at lists.osgeo.org
      Type:  enhancement  |      Status:  new                      
  Priority:  major        |   Milestone:  6.4.0                    
 Component:  default      |     Version:  svn-develbranch6         
Resolution:               |    Keywords:                           
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Comment (by glynn):

 Replying to [ticket:169 cmbarton]:
 > I'd like to request a module with a suggested name of r.edit. This would
 let you specify an existing map to edit, and then specify the xy
 coordinages, cat, and optionally label of a cell to change. Preferably,
 the input parameter would accept a list of
 >
 > x y cat [label],x y cat [label],x y cat [label],...
 >
 > so that multiple cells could be changed.

 Specifying the label is bogus. The category is a property of the cell, but
 the label is a property of the category. You can't have two cells with the
 same category but different labels.

 > I realize that you can accomplish this with r.in.poly and r.patch and
 have even made a script to do it. However, it is a clunky work around,
 slower than directly changing values, seems to have some difficulties in
 maintaining labels for fp maps.

 r.in.xyz and r.patch would seem more suitable.

 Also, note that r.* modules don't generally modify maps "in-place"; they
 create new maps based upon existing maps. There are some exceptions, but
 these are usually low-level administrative utilities such as r.null and
 r.compress.

 Also, there's no performance benefit to in-place modification. The
 underlying libraries don't actually support in-place modification; you
 have to create a completely new map then replace the existing map upon
 completion.

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Ticket URL: <http://trac.osgeo.org/grass/ticket/169#comment:2>
GRASS GIS <http://grass.osgeo.org>