[GRASS-dev] [GRASS GIS] #3016: Add option to set scalebar length

[GRASS GIS]

#3016: Add option to set scalebar length
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  Reporter:  annakrat     |      Owner:  grass-dev@…
      Type:  enhancement  |     Status:  new
  Priority:  normal       |  Milestone:  7.3.0
 Component:  Display      |    Version:  unspecified
Resolution:               |   Keywords:  d.barscale, gsoc2016, cartography
       CPU:  Unspecified  |   Platform:  All
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Comment (by annakrat):

 Replying to [comment:2 lazaa]:
 > Replying to [comment:1 wenzeslaus]:
 > > I think the size should be specified in map units, for example user
 can say `size=250` to get 250m scale bar. This seems like a simple and
 actually a desired option. What are the units there probably depend on the
 rest of the implementation or interface of d.barscale. With the current
 implementation it would be probably meters by default but it should be
 feet when the `-f` is used.
 >
 > I added option{{{length}}}, so the size can be specified in map units.
 By defaults in meters, with {{{-f}}} flag in feet. I'm not sure it's the
 best solution. If user wants a barscale of size let's say 150 miles he has
 to convert 150 miles into feet.

 I was thinking it would be good to add new option `units` with options
 meters, kilometers, feet and miles instead of the flag `-f`. This flag
 would have to stay there for compatibility reasons but would be marked
 obsolete. By default it would use map units, see m.measure for example.

 Also having option to set custom label (overriding the unit) would enable
 working in XY location with mm for example. I think it would bring more
 flexibility comparing to the `-u` flag, so users could choose whether they
 want 'meters' (current default) or 'm' or name of the units in other
 languages.

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Ticket URL: <https://trac.osgeo.org/grass/ticket/3016#comment:3>
GRASS GIS <https://grass.osgeo.org>