[GRASS-dev] [GRASS GIS] #1385: r3.in.ascii man page vs. r3.in.ascii source code

[GRASS GIS]

#1385: r3.in.ascii man page vs. r3.in.ascii source code
-------------------------+--------------------------------------------------
 Reporter:  hamish       |       Owner:  grass-dev@…              
     Type:  defect       |      Status:  new                      
 Priority:  normal       |   Milestone:  6.4.2                    
Component:  Docs         |     Version:  svn-develbranch6         
 Keywords:  r3.in.ascii  |    Platform:  Linux                    
      Cpu:  x86-64       |  
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 Hi,

 the man page for `r3.in.ascii` (6.5svn) states:

  ''Note lower-left (SW) corner of the bottom level comes first!  This
 array format, where EW is preserved but NS is flipped, is some-times known
 as "ij" coordinates.  This is opposite to r.in.ascii's format, which
 places the SW corner at the beginning of the last row of data.''

 but then shows data format example like:
 {{{
 ,y1,
 ,y2,
 ,y3,
 }}}
 (although I think I might have added that :)

 and importing data with NW corner as the first bytes of the file, then
 `r3.to.rast` to split into layers seems to successfully display north-up.
 So either the man page or the `r3.in.ascii` code has got it backwards..?

 I also notice that `r3.out.vtk` exports celldata with the data south-up
 within the ascii.vtk file, but I'm not sure if that is part of the VTK
 design, or the export module flipping what it doesn't actually have to. ??


 ----
 tangent:
 I don't know Paraview well enough to reliably say which way 'should' be up
 there. The first thing I notice in Paraview 3.8.0 after loading the data,
 apply, Display|Style->representation,Surface + Color->Color by->''layer
 name'' is that the top level is on the bottom and the bottom layer is on
 the top. again in the display tab setting Transformation->Scale->z to -1
 makes it ok, but it gets very dark, as if it is all in shadow.  (test data
 is cube containing 0/1 boolean values, similar to what r.to.rast3elev
 would create from a 2.5D DEM for land/air.  I'm still struggling to
 visualize that well in NVIZ or paraview.)
 ??or perhaps I set top: and bottom: backwards in the `r3.in.ascii` header?
 `r3.to.rast` shows level 0001 as top layer, level 25 (of 25) as bottom
 layer. (data is all below sea level)


 Hamish

 ps- don't try searching in trac for `r3.in.ascii`, as it treats the `r3`
 as svn rev3 which is almost every file in the grass 5 source code! The web
 browser does not enjoy it.

-- 
Ticket URL: <https://trac.osgeo.org/grass/ticket/1385>
GRASS GIS <http://grass.osgeo.org>