[GRASS-dev] [GRASS GIS] #3043: Change default color table

GRASS GIS trac at osgeo.org
Mon May 30 14:48:37 PDT 2016

#3043: Change default color table
  Reporter:  wenzeslaus   |      Owner:  grass-dev@…
      Type:  enhancement  |     Status:  new
  Priority:  blocker      |  Milestone:  7.2.0
 Component:  Raster       |    Version:  svn-trunk
Resolution:               |   Keywords:  r.colors, d.rast, rainbow
       CPU:  Unspecified  |   Platform:  Unspecified

Comment (by wenzeslaus):

 Replying to [comment:5 mlennert]:
 > Generally, it seems to me that rainbow and bcyr provide greater

 This might be true is some cases, or at least it seems this way. However,
 the opposite is true in the example I just posted which is a slightly
 titled plane with waves on it created using:

 g.region cols=500 rows=300 n=-300 s=-600 w=0 e=500
 r.mapcalc "x = col() / 10 + 2 * cos(col() * 100)" && r.colors map=x

 The waves are visible with `viridis` (first) and `gray` (last) but
 `rainbow` (second) shows them a lot in the middle while not at all in the
 green region. `bcyr` (third) shows waves on the sides but not so much in
 the middle, they seem to be completely lost in light blue and yellow


 See more in work by [http://peterkovesi.com/projects/colourmaps/ Peter
 Kovesi] (Colour Maps with Uniform Perceptual Contrast).

 In some other cases `rainbow` overly emphasizes features or even creates
 (suggests) features which are not there. The example above doesn't show
 this except for the region between light and dark blue where the lines
 (waves) are much more prominent.

 It must be noted that a lot of color tables, even some rainbow-like ones
 when they are ''perceptually uniform'', can perform good in this test.

Ticket URL: <https://trac.osgeo.org/grass/ticket/3043#comment:9>
GRASS GIS <https://grass.osgeo.org>

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