[GRASS-dev] [GRASS GIS] #1851: Misalignment of an imported .asc raster

[GRASS GIS]

#1851: Misalignment of an imported .asc raster
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 Reporter:  pcav         |       Owner:  grass-dev@…              
     Type:  defect       |      Status:  new                      
 Priority:  normal       |   Milestone:  6.4.3                    
Component:  Raster       |     Version:  6.4.2                    
 Keywords:               |    Platform:  Unspecified              
      Cpu:  Unspecified  |  
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Comment(by mmetz):

 Replying to [ticket:1851 pcav]:
 > * import (-o) the .asc file from
 https://www.dropbox.com/s/w60ywwddl3aj03h/cavallini.zip
 > * r.to.vect
 > (you can see the results of these operations in the location, in the zip
 above)
 >
 >
 > Display raster and vector, either in GRASS or in QGIS (in this second
 you can also load the original raster).

 In the first (GRASS), you can also load the original raster via
 r.external.
 >
 > Results: the original raster and the derived vector align perfectly, the
 imported raster shows shifts while zooming in and out. See attached
 screenshots as an example.

 Looking at the metadata:

 {{{
 > g.region -g zoom=GR23B07 rast=GR23B07
 n=4895155
 s=4894780
 w=1568780
 e=1569043
 nsres=1
 ewres=1

 > v.info -g map=G23B07vectV
 north=4895155
 south=4894780
 east=1569043
 west=1568780
 }}}

 The raster and the vector are exactly aligned, also when displayed with
 GRASS wxGUI at different zoom levels, both with GRASS 6.4 and GRASS 7.

 The attached screenshots 33.png and shot2.png are not made from GRASS
 display with the location in cavallini.zip. Please try to display the
 imported raster map and the derived vector map in the GRASS location in
 cavallini.zip using GRASS.

 >
 > Additionally, in qgis-dev I get errors querying the raster:
 > 168 bytes expected but 3200000 byte were read from qgis.d.rast

 File a bug for qgis?
 >
 > Tested on 3 different machines (Debian Unstable, Ubuntu, Windows).

 Unfortunately, the misalignment is not reproducible by others (at least 3
 different people with different OS's and different GRASS versions).

 Markus M

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Ticket URL: <http://trac.osgeo.org/grass/ticket/1851#comment:1>
GRASS GIS <http://grass.osgeo.org>