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NAME

       d.legend   -  Displays  a  legend  for  a  raster  map in the active frame of the graphics
       monitor.

KEYWORDS

       display, cartography

SYNOPSIS

       d.legend
       d.legend help
       d.legend   [-mvcnsf]   map=name    [color=string]      [lines=integer]      [thin=integer]
       [labelnum=integer]           [at=bottom,top,left,right]          [use=catnum[,catnum,...]]
       [range=min,max]   [--verbose]  [--quiet]

   Flags:
       -m
           Use mouse to size & place legend

       -v
           Do not show category labels

       -c
           Do not show category numbers

       -n
           Skip categories with no label

       -s
           Draw smooth gradient

       -f
           Flip legend

       --verbose
           Verbose module output

       --quiet
           Quiet module output

   Parameters:
       map=name
           Name of raster map

       color=string
           Sets the legend's text color
           Options:
           red,orange,yellow,green,blue,indigo,violet,white,black,gray,brown,magenta,aqua,grey,cyan,purple
           Default: black

       lines=integer
           Number of text lines (useful for truncating long legends)
           Options: 0-1000
           Default: 0

       thin=integer
           Thinning factor (thin=10 gives cats 0,10,20...)
           Options: 1-1000
           Default: 1

       labelnum=integer
           Number of text labels for smooth gradient legend
           Options: 2-100
           Default: 5

       at=bottom,top,left,right
           Placement as percentage of screen coordinates (0,0 is lower left)
           bottom,top,left,right
           Options: 0-100

       use=catnum[,catnum,...]
           List of discrete category numbers/values for legend

       range=min,max
           Use a subset of the map range for the legend (min,max)

DESCRIPTION

       d.legend displays a legend for a user-specified raster map layer in the  active  frame  on
       the graphics monitor.

       The  user  can  run  d.legend  either  non-interactively  or  interactively.   If the user
       specifies the name of a raster map layer on the command line, the program  will  run  non-
       interactively.   Default  legend  text  color  and  position  will be used unless the user
       specifies other values on the command line.

       Alternately, the user can simply type d.legend on the command  line;  in  this  case,  the
       program will prompt the user for parameter values using the standard GRASS GUI interface.

NOTES

       The legend's default size is based on the dimensions of the active frame, specifically its
       height.  d.legend will only obscure those portions  of  the  active  frame  that  directly
       underlie the legend.

       When  using  the  mouse  or  at to size & place the legend, a user may create a horizontal
       legend by making the box wider than it is tall.

       Raster maps based on floating  point  values  will  display  smoothed,  from  greatest  to
       smallest  value,  while  categorial raster maps will display in order, from top to bottom.
       Horizontal legends will always be smoothed. If the box is defined with  inverted  y-values
       or  an  inverted  range,  the  legend  will automatically flip. If this is not the desired
       result, the -f flag may be used to flip it back.

       If the user attempts to display a very long legend in a relatively  short  display  frame,
       the  legend  may  appear  in  unreadably  small  text, or even revert to a smooth gradient
       legend. Use the lines, thin, use, range,  and/or  -n  options  to  reduce  the  number  of
       categories to be displayed, or the -s flag to force a smooth gradient legend.

       The  lines  option  will  display  the  first  number  of categories, as defined by value,
       contained in the raster map. When used with the -n flag, it takes on a new meaning: "up to
       category  #".  When used with both thin and the -n flag, its meaning becomes more obscure.
       When using lines, auto-scaled text similar to "4 of 16 categories" will be placed  at  the
       bottom of the legend.

       The  thin  option  sets  the thinning factor. For raster maps with a 0th category, thin=10
       gives cats [0,10,20,...]. For raster maps starting  at  category  1,  thin=10  gives  cats
       [1,11,21,...].

       The  use  option  lets the user create a legend made up of arbitrary category values. e.g.
       use=1000,100,10,0,-10,-100,-1000

       The range option lets the user define the minimum and maximum categories to be used in the
       legend.  It may also be used to define the limits of a smooth gradient legend created from
       a raster containing floating point values. Note the color scale will  remain  faithful  to
       the  category values as defined with r.colors, and the range may be extended to the limits
       defined by the r.colors color map.

       The flag -n is useful for categorial maps, as it suppresses the  drawing  of  non-existing
       categories (otherwise the full range is shown).

       Vertical  legends produced with d.legend will place text labels to the right of the legend
       box, horizontal legends will place text below. This text will be auto-scaled to fit within
       the frame, reducing the size of the legend if necessary. Legends positioned with the mouse
       or with the at option will not auto-scale text, in order to provide more  control  to  the
       user.  Smaller text may be obtained in this case by reducing the height of the box. The -c
       and -v flags may  be  used  to  suppress  the  display  of  category  numbers  and  labels
       respectively, or used together to suppress all text of categorial raster maps.

       The  text produced from floating-point raster maps will automatically create output with a
       meaningful number of significant digits. For very small values, numbers will be  expressed
       in scientific notation, e.g. "1.7e-9".

       Legends  placed with the mouse are not saved to the display window's history for automatic
       redraw. By setting the Debug level to 1 (see g.gisenv) the corresponding at setting can be
       determined.

       Note  that old scripts which relied on setting lines greater than the number of categories
       to scale the legend may no longer produce the desired output,  although  the  auto-scaling
       should still produce something that looks good in this case.

SEE ALSO

       d.barscale
       d.colors
       d.colortable
       d.erase
       d.font
       d.font.freetype
       d.grid
       d.rast
       d.rast.leg
       d.text
       d.text.freetype
       d.vect.thematic
       d.what.rast
       g.gisenv
       r.reclass

AUTHORS

       Bill Brown, U.S. Army Construction Engineering Research Laboratories
       Late 2002: Rewrite of much of the code. Hamish Bowman, Otago University, New Zealand
       Additional improvements from various authors

       Last changed: $Date: 2005-10-28 01:20:21 +0200 (Fri, 28 Oct 2005) $

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       © 2003-2010 GRASS Development Team