[GRASS-dev] [GRASS GIS] #2336: Vector map shifted in the map display

[GRASS GIS]

#2336: Vector map shifted in the map display
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 Reporter:  hcho          |       Owner:  grass-dev@…              
     Type:  enhancement   |      Status:  new                      
 Priority:  normal        |   Milestone:  7.1.0                    
Component:  Display       |     Version:  svn-trunk                
 Keywords:  d.rast.arrow  |    Platform:  All                      
      Cpu:  All           |  
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 I don't have this problem until I draw flow arrows (Add raster flow
 arrows). When I click this menu, I'm asked to change the display
 resolution. If I click No, the resolution looks very high (I think it's 1
 arrow per pixel) and everything is just green (the default arrow color).
 If I click Yes as recommended, raster cells in the display become
 perfectly aligned with the display borders and arrows are drawn as
 expected. So far, so good.

 Now, if I add a polygon vector map representing cell boundaries, the lines
 don't perfectly match with the raster cells (shown in the attached
 screenshot). IMO, if I choose to align raster cells with the display
 borders, vector coordinates have to be transformed such that they are also
 snapped to the nearest cell vertices... Hmm... in some case, we may not
 want this.

 OR can we not change the display resolution at all and display arrows
 correctly (one arrow per cell, not one arrow per pixel)?

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Ticket URL: <http://trac.osgeo.org/grass/ticket/2336>
GRASS GIS <http://grass.osgeo.org>