[GRASS-dev] [GRASS GIS] #2100: r.proj bounding box too small by half a cell size (-g or -p):

GRASS GIS trac at osgeo.org
Tue Dec 23 13:58:43 PST 2014


#2100: r.proj bounding box too small by half a cell size (-g or -p):
-------------------------+--------------------------------------------------
 Reporter:  awickert     |       Owner:  grass-dev@…              
     Type:  defect       |      Status:  new                      
 Priority:  normal       |   Milestone:  7.0.0                    
Component:  Default      |     Version:  unspecified              
 Keywords:  r.proj       |    Platform:  Linux                    
      Cpu:  Unspecified  |  
-------------------------+--------------------------------------------------

Comment(by mmetz):

 Replying to [comment:1 glynn]:
 > Replying to [ticket:2100 awickert]:
 >
 > The border-walking code uses cell centres in all cases (i.e. when
 performing projection as well as when displaying the bounding box with
 -p/-g).
 >
 > It's possible that this is intentional, to avoid issues when the
 north/south edges of either the current region or the input map extend to
 the poles.

 These issues arise only when region cropping is done for real
 reprojection, and here the half-cell offset does not apply because the
 cropped output region is aligned to the original output region. The
 original output region in turn has been previously defined by the user.

 Thus the reported bug applies only to r.proj -[p|g], introduced in r40560.
 r.proj -[p|g] prints the real extents as of r63697. These real extents
 need to be interpreted (and possibly adjusted) by the user with regard to
 the input map extents and output projection.

-- 
Ticket URL: <https://trac.osgeo.org/grass/ticket/2100#comment:4>
GRASS GIS <http://grass.osgeo.org>



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