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NAME

       r.category  - Manages category values and labels associated with user-specified raster map
       layers.

KEYWORDS

       raster, category

SYNOPSIS

       r.category
       r.category --help
       r.category      map=name       [cats=range[,range,...]]         [values=float[,float,...]]
       [separator=character]          [raster=name]          [rules=name]         [format=string]
       [coefficients=mult1,offset1,mult2,offset2]   [--help]  [--verbose]  [--quiet]  [--ui]

   Flags:
       --help
           Print usage summary

       --verbose
           Verbose module output

       --quiet
           Quiet module output

       --ui
           Force launching GUI dialog

   Parameters:
       map=name [required]
           Name of raster map

       cats=range[,range,...]
           Category values
           Example: 1,3,7-9,13

       values=float[,float,...]
           Comma separated value list
           Example: 1.4,3.8,13

       separator=character
           Field separator
           Special characters: pipe, comma, space, tab, newline
           Default: tab

       raster=name
           Raster map from which to copy category table

       rules=name
           File containing category label rules (or "-" to read from stdin)

       format=string
           Default label or format string for dynamic labeling
           Used when no explicit label exists for the category

       coefficients=mult1,offset1,mult2,offset2
           Dynamic label coefficients
           Two pairs of category multiplier and offsets, for $1 and $2

DESCRIPTION

       r.category prints the category values and labels for the raster  map  layer  specified  by
       map=name to standard output. You can also use it to set category labels for a raster map.

       The  user  can  specify  all  needed  parameters  on the command line, and run the program
       non-interactively. If the user does not specify any categories (e.g., using  the  optional
       cats=range[,range,...]   argument),  then all the category values and labels for the named
       raster map layer that occur in the  map  are  printed.   The  entire  map  is  read  using
       r.describe,  to determine which categories occur in the map. If a listing of categories is
       specified, then the labels for  those  categories  only  are  printed.  The  cats  may  be
       specified  as  single  category  values,  or  as  ranges  of  values.  The  user  may also
       (optionally) specify that a field separator other than a space or tab be used to  separate
       the  category  value  from  its  corresponding  category label in the output, by using the
       separator=character|space|tab option  (see  example  below).  If  no  field  separator  is
       specified by the user, a tab is used to separate these fields in the output, by default.

       The  output  is  sent  to  standard  output in the form of one category per line, with the
       category value first on the  line,  then  an  ASCII  TAB  character  (or  whatever  single
       character  or  space  is  specified using the separator parameter), then the label for the
       category.

NOTES

       Any ASCII TAB characters which may be in the label are replaced by spaces.

       The output from r.category can be redirected into a file, or piped into another program.

   Input from a file
       The rules option allows the user to assign category labels from values found  in  a  file.
       The  label can refer to a single category, range of categories, floating point value, or a
       range of floating point values.  The format is given as follows (when separator is set  to
       colon; no white space must be used after the separator):
       cat:Label
       val1:val2:Label
       If the filename is given as "-", the category labels are read from stdin

   Default and dynamic category labels
       Default  and dynamic category labels can be created for categories that are not explicitly
       labeled.  The coefficient line can be followed by explicit category labels which  override
       the format label generation.
          0:no data
          2:     .
          5:     .               ## explicit category labels
          7:     .
       explicit labels can be also of the form:
          5.5:5:9 label description
          or
          15:30  label description

       In the format line

           ·   $1 refers to the value num*5.0+1000 (ie, using the first 2 coefficients)

           ·   $2 refers to the value num*5.0+1005 (ie, using the last 2 coefficients)
       $1.2 will print $1 with 2 decimal places.

       Also,  the  form  $?xxx$yyy$  translates into yyy if the category is 1, xxx otherwise. The
       $yyy$ is optional. Thus

       $1 meter$?s

       will become:
       1 meter (for category 1)
       2 meters (for category 2), etc.

       format=’Elevation: $1.2 to $2.2 feet’   ## Format Statement
       coefficients="5.0,1000,5.0,1005"   ## Coefficients

       The format and coefficients above would be used to generate  the  following  statement  in
       creation of the format appropriate category string for category "num":

       sprintf(buff,"Elevation: %.2f to %.2f feet", num*5.0+1000, num*5.0*1005)

       Note:  while  both  the  format and coefficient lines must be present a blank line for the
       format string will effectively suppress automatic label generation.

       To use a "$" in the label without triggering the plural  test,  put  "$$"  in  the  format
       string.

       Use  ’single  quotes’  when  using  a  "$"  on  the  command  line to avoid unwanted shell
       substitution.

EXAMPLES

       North Carolina sample dataset:

   Printing categories
       r.category map=landclass96
       1    developed
       2    agriculture
       3    herbaceous
       4    shrubland
       5    forest
       6    water
       7    sediment
       prints the values and labels associated with all of  the  categories  in  the  landclass96
       raster map layer.

       r.category map=landclass96 cats=2,5-7
       2    agriculture
       5    forest
       6    water
       7    sediment
       prints  only  the  category values and labels for landclass96 map layer categories 2 and 5
       through 7.

       r.category map=landclass96 cats=3,4 separator=comma
       3,herbaceous
       4,shrubland
       prints the values and labels for landclass96 map layer categories 3 and 4,  but  uses  ","
       (instead  of  a  tab)  as  the  character separating the category values from the category
       values in the output.

   Adding categories
       Example for defining new category labels, using a colon as separator:
       r.category diseasemap separator=":" rules=- << EOF
       1:potential absence
       2:potential presence
       EOF
       This sets the categoy values 1 and 2 to respective text labels.  Alternatively, the  rules
       can be stored in an ASCII text file and loaded via the rules parameter.

SEE ALSO

       UNIX Manual entries for awk and sort

        d.what.rast, r.coin, r.describe, r.support

AUTHORS

       Michael Shapiro, U.S. Army Construction Engineering Research Laboratory
       Hamish Bowman, University of Otago, New Zealand (label creation options)

       Last changed: $Date: 2017-02-12 20:35:44 +0100 (Sun, 12 Feb 2017) $

SOURCE CODE

       Available at: r.category source code (history)

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       © 2003-2018 GRASS Development Team, GRASS GIS 7.4.0 Reference Manual