[GRASS-dev] [GRASS GIS] #2714: wish: logarithmic legend for raster maps

[GRASS GIS]

#2714: wish: logarithmic legend for raster maps
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  Reporter:  veroandreo   |      Owner:  grass-dev@…
      Type:  enhancement  |     Status:  new
  Priority:  normal       |  Milestone:  7.0.5
 Component:  Display      |    Version:  svn-releasebranch70
Resolution:               |   Keywords:  d.legend, gsoc2016, cartography
       CPU:  x86-64       |   Platform:  All
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Comment (by lazaa):

 Replying to [comment:13 veroandreo]:
 > Replying to [comment:11 lazaa]:
 > > Thanks for real data, it was much easier find the mistake. It gives
 better results now.
 >
 > Yes, it is better indeed. But check how the scale for chlorophyll
 proposed by NASA looks like (and how a logarithmic scale looks like in
 general):
 http://oceancolor.gsfc.nasa.gov/images/CHL_chlor_a_colorscale.png
 >
 > Values should be equally spaced, "graphically" speaking (for example:
 0.01, 0.03, 0.1, 0.3, 1.0, 3.0, 10.0) and therefore more space in the
 color palette is needed for lower values, i.e.: more space for "blues"
 "cyans" and "greens" in your example (there's still a lot of red).

 You're right, I used wrong formula to calculate the scale.

 >
 > > ...
 > >
 > > but maybe I should add new option so user can determine how many
 digits display?
 >
 > This could be useful in general :)

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Ticket URL: <https://trac.osgeo.org/grass/ticket/2714#comment:14>
GRASS GIS <https://grass.osgeo.org>