1r.describe(1)                 Grass User's Manual                r.describe(1)
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NAME

6       r.describe   -  Prints  terse list of category values found in a raster
7       map layer.
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KEYWORDS

10       raster
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SYNOPSIS

13       r.describe
14       r.describe help
15       r.describe [-1rqdi] map=name  [nv=string]   [nsteps=integer]
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17   Flags:
18       -1  Print the output one value per line
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20       -r  Only print the range of the data
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22       -q  Quiet
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24       -d  Use the current region
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26       -i  Read fp map as integer
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28   Parameters:
29       map=name
30           Name of input raster map
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32       nv=string
33           string representing no data cell value Default: *
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35       nsteps=integer
36           number of quantization steps Default: 255
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DESCRIPTION

39       r.describe prints a terse listing of category values found in  a  user-
40       specified raster map layer.
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42   PROGRAM USE
43       The  user  can  select  one  of  the  following two output reports from
44       r.describe:
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46       (1) RANGE.
47              A range of category values found in the raster map layer will be
48              printed.   The  range  is  divided into three groups:  negative,
49              positive, and zero.  If negative values occur, the  minimum  and
50              maximum  negative  values  will  be printed.  If positive values
51              occur, the minimum and maximum positive values will be  printed.
52              If zero occurs, this will be indicated.
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54       (2) FULL LIST.
55              A  list of all category values that were found in the raster map
56              layer will be printed.
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58       The following sample output from r.describe: 0 2-4 10-13
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60       means that category data values 0, 2  through  4,  and  10  through  13
61       occurred in the named map layer.
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63       The user must choose to read the map layer in one of two ways:
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65       (1) DIRECTLY.
66              The  current geographic region and mask are ignored and the full
67              raster map layer is read.  This method is  useful  if  the  user
68              intends to reclassify or rescale the data, since these functions
69              (r.reclass and r.rescale) also  ignore  the  current  geographic
70              region and mask.
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72       (2) REGIONED and MASKED.
73              The  map  layer  is  read  within the current geographic region,
74              masked by the current mask.
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76   NON-INTERACTIVE PROGRAM USE
77       r.describe examines a user-chosen raster map layer.  If run  non-inter‐
78       actively, the layer name must be supplied on the command line.
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80       A  compact  list  of  category values that were found in the data layer
81       will be printed.
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83       Following is a sample output: 0 2-4 10-13
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85   FLAGS
86       -1     Print the output one value per  line,  instead  of  the  default
87              short form.  In the above example, the -1 option would output:
88              0
89              2
90              3
91              4
92              10
93              11
94              12
95              13
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98       -r     Only  print the range of the data.  The highest and lowest posi‐
99              tive values, and the highest and  lowest  negative  values,  are
100              output. In the above example, the -r option would output: 0 2 13
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102       If  the  -1 option is also specified, the output appears with one cate‐
103       gory value per line.
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105       -q     Quiet. The -q option will tell r.describe  to  be  silent  while
106              reading  the raster file.  If not specified, program percentage-
107              completed messages are printed.
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109       -d     Use  the  current   geographic   region   settings.    Normally,
110              r.describe  will read the data layer directly, ignoring both the
111              current  region  settings  and  mask.   The  -d   option   tells
112              r.describe to read the map layer in the current region masked by
113              the current mask (if any).
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115   Parameters:
116       map=name
117              Name of raster map.
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119       nv=string
120              String representing no data cell value.
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122       nsteps=value
123              Number of quantization steps.
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NOTES

126       The range report will generally run faster than the full list.
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SEE ALSO

129       g.region, r.reclass, r.rescale
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AUTHOR

132       Michael Shapiro, U.S. Army Construction Engineering Research Laboratory
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134       Last changed: $Date: 2006/04/13 19:01:37 $
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136       Full index
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140GRASS 6.2.2                                                      r.describe(1)