[GRASS-dev] [GRASS GIS] #3077: r.colors: flag to output color table type and value range

[GRASS GIS]

#3077: r.colors: flag to output color table type and value range
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 Reporter:  neteler             |      Owner:  grass-dev@…
     Type:  enhancement         |     Status:  new
 Priority:  normal              |  Milestone:  7.2.0
Component:  Raster              |    Version:  svn-trunk
 Keywords:  r.colors, gsoc2016  |        CPU:  All
 Platform:  All                 |
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 r.colors would benefit from more detailed output

  * flag to output of type of a color table (relative, absolute, ...)
  * flag to output the ranges of all color tables (min, max in case of
 absolute tables)

 At time, the user does not know if a predefined color table covers the
 range of the input map. Explanations on this would quite help but they
 should be generated automatically:

 Examples:

  * aspect
    * based on degree? (it is in percent)
  * haxby: relative colors for bathymetry or topography
    * "relative" is given, fine
  * ndvi: Normalized Difference Vegetation Index colors
    * ... (-1.0 .. +1.0)
  * ndwi: Normalized Difference Water Index colors
    * ... (-200 .. +200)
  * precipitation
    * starts at 0, ends at 7000
    * suggestion: instead of "precipitation: precipitation color table
 (0..2000mm)" which is incorrect anyway, print e.g. "precipitation:
 precipitation color table [%s..%smm),min, max)"

 etc.

 In essence: relative color tables will cover "any" range while absolute
 color tables do not. This should become clear from the description without
 reverse engineering the color files.

 Effectively, more values should be added to lib/gis/colors.desc in an
 automated way.

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Ticket URL: <https://trac.osgeo.org/grass/ticket/3077>
GRASS GIS <https://grass.osgeo.org>