[GRASS-dev] Re: [GRASS GIS] #31: NVIZ in GRASS6.2.3 (some problems)

[GRASS GIS]

#31: NVIZ  in GRASS6.2.3 (some problems)
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  Reporter:  clerici  |       Owner:  grass-dev at lists.osgeo.org
      Type:  defect   |      Status:  new                      
  Priority:  major    |   Milestone:  6.4.0                    
 Component:  default  |     Version:  6.2.3                    
Resolution:           |    Keywords:  nviz                     
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Comment (by clerici):

 3) In the Surface panel the masking doesn't have any effect on 'fine'
 surfaces but only on 'wire' surfaces and vectors maps.

 Example 1.
 Enter nviz and load 'elevation.dem' and 'streams'
 In the Surface panel press Draw mode and select Both (to display Wire and
 Fine surface); press Coarse Style and select Wire.
 Press Surface Attribute and select mask: mask not set. In the Change
 attribute panel press New Map and load the map 'fields'. Pressing Accept
 the wire and streams are deleted in the area were 'fields' has values
 different from null, but the Fine surface is not.

 Example 2.
 Construction of a DEM with zero elevations:
 r.mapcalc "elev1000.dem=if(elevation.dem <= 1200,0,elevation.dem-1200)"
 Enter nviz and load 'elevation1000.dem' and 'streams'
 In the Surface panel press Draw mode and select Both (to display Wire and
 Fine surface); press Coarse Style and select Wire.
 In the Surface panel select Mask Zeros by: Elevation.
 Pressing Draw the wire and streams are deleted in the area were
 elev1000.dem has zero values, but the Fine surface is not.


 5) In the Surface panel the Transparency function has a strange behaviour
 with the 'constant' elevation surfaces. When a transparency.........

 Step-by-step procedure.
 Enter nviz and load 'elevation.dem'.
 In the Surface panel press New.
 In the Change Attribute panel press New Constant and enter a value of
 3000.
 The new plane at constant elevation partially overly 'elevation.dem'.
 Press Surface attribute and select transparency: transparency not set. In
 the Change Attribute panel press New Constant and define the transparency
 value (130 for example), then Accept.
 a) Press DRAW: the surface is hidden under elevation.dem (and remain
 hidden even if you change the surfaces' orientation).
 b) Press Draw Current in the Surface panel: transparency is effective, but
 if you press DRAW or change the surfaces' orientation, the plane is hidden
 again by elevation.dem.
 c) Press Draw Current many times: the transparency reduces progressively,
 but the previously selected value of transparency (130) doesn't change.
 May be this is due to the redrawing of the same surface many times?

 This seems to happen only with surfaces at constant elevation (I tried
 also with two planes, and the problem is the same). With 'elevation.dem'
 or 'elevation.dtet' transparency works fine.

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Ticket URL: <http://trac.osgeo.org/grass/ticket/31#comment:2>
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